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This page documents oversight tools and provides guidelines and suggestions for their use. It describes procedures existing on Wikimedia Wikispecies, but might also be used as a guide for other Wikimedia wikis (with local adjustments).

This page is a basic how-to guide explaining how to carry oversight actions. It does not cover any relevant Wikimedia policies, so please familiarise yourself with them before doing anything described here.

This guide was written from the perspective of a Wikimedia Wikispecies oversighter, but you might find it helpful even if you come from a different wiki, as most of the procedures should apply to all MediaWiki-based sites.

For consistency purposes, the word "oversighters" will from now on refer to users with the oversight permission (see definition); the act of hiding data from regular editors and administrators will be referred to as "suppression".

Note: This is in no way an official Wikispecies guide, but a mere attempt at documenting community lore, increasing our bus factor, and creating a how-to for our internal usage. It comes with no warranty, so make sure you know what you're doing!


File suppressions are the most common examples of using suppression on Wikimedia Wikispecies, simply because of the scope of this project. Depending on the exact situation, there are several ways of achieving the same result; this section will cover only the most typical scenarios.

Suppressing all file revisions


Existing files


Suppressing existing files is pretty straightforward:

  1. Go to the regular deletion menu (or press alt + shift + d on your keyboard);
  2. Add a reason for the action in the "Other/additional reason:" field, make sure to tick the "Suppress data from administrators as well as others" option and press "Delete page".

In this specific case, it is especially important to double-check if the "Suppress data from administrators as well as others" option is ticked. If you do forget to tick it, you'll need to restore the file, repeat the procedure again, and suppress a few more log entries than would've been necessary; additionally, your actions will be temporarily visible to non-oversighters, which might not be exactly what you were after.

This basic functionality, as always, comes with a price: it does not allow you choose what property (edit summary, user name/IP address or file revision) to suppress, but simply suppresses them all in one go. It hides all edits made to the file page from users' deleted contributions and suppresses all file revisions. However, it does not influence previous log entries for the file, so you might need to suppress them manually (see #Log-related suppressions).

Deleted files


This is by far the most common example of suppressions performed here on Wikispecies. Due to the small number of local oversighters and the ever-rising number of uploads, it is virtually impossible for us to patrol all uploads at all times; therefore, most of the files are already deleted before being brought to our attention.

There are two ways of managing suppressions of files that had already been deleted:

  1. The quick way: simply restore the file and suppress it directly from the deletion menu (see #Existing files and #Log-related suppressions for more details). This method has several disadvantages: (1) it makes the file temporarily visible to non-administrators, (2) it doesn't allow you to choose what properties to suppress, and (3) it produces a new deletion (restoration) log entry; on the other hand, it is quickest and lets you suppress all file revisions and edits in one action.
  2. The slow way. This method doesn't restore files and allows performing per-property and per-revision suppressions, but takes a lot of time and produces numerous actions in the suppression log.
    1. From the file undeletion page (Special:Undelete), go to the File history section and click on (show/hide);
    2. Next, tick the "Hide file content" and "Suppress data from administrators as well as others" options. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision". If necessary, tick the other options (edit summary or username/IP address);
    3. If required, repeat this step for remaining file revisions and edits. Note: If you had suppressed all file revisions and realised that you need to suppress all edits, too, don't suppress them one by one; just restore them and suppress them the usual way (see #Existing files);

Suppressing specific file revisions


To suppress a specific file revision:

  1. On the file page, scroll down to the "File history" section and press (show/hide) next to the thumbnail of the file revision you want to suppress;
  2. Next, tick the relevant properties you want to suppress and the "Suppress data from administrators as well as others" option. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".
  3. Note: If you want to suppress the contents of the "Comment" box, for instance because they reveal the real name of a user, tick the "Hide edit summary" option. However, due to bug #38497, you also need to remember to suppress the upload log entry of the file and the edit summary at the history page. See #Log-related suppressions and #Suppressing previous revisions for instruction on how to do that.

Similarly to regular page revisions, you cannot suppress the current revision of a file. If, for instance, the file that you need to suppress reveals personal information of a user (be it through the user name, upload comment or through the file content itself), you need to upload a new version of it, and then suppress the previous one.

This is most common when it comes to suppressing previous versions of files that reveal non-public information through their Exif data; see the section below for details.

Removing Exif data


Once in a while, users request that we suppress file revisions that reveal their non-public private information (real names, e-mail addresses, geographical coordinates, etc.) through the {{w|Exchangeable image file format|Exif data}}. This is especially tricky, since there is no built-in mechanism to remove this data through MediaWiki, and is only achievable by uploading a new version and suppressing the previous one (see above).

There are tens of manuals on how to manipulate Exif data available on the Internet, depending on your operating system and tool preferences. Here's how it can be done on a Unix-like machine using {{w|ExifTool|exiftool}} via the command line:

Get a full list of all Exif tags for the file:

$ exiftool -s [YOURFILE]

To delete specific tags, just run:

$ exiftool -Tag= -DifferentTag= [YOURFILE]

As you see, exiftool can remove multiple tags in one command. Remember that exiftool tag names never contain spaces and that some of the tags are not writable (see a full list of exiftool tag names and the FAQ for more information).


Suppressing previous revisions


Suppressing previous revisions of a page, or certain properties thereof, is possibly the easiest action an oversighter can perform.

To suppress a single revision:

  1. Go to the history page (or press alt + shift + h on your keyboard);
  2. Select the relevant revision and press "Show/hide selected revisions";
  3. Next, tick the property you need to suppress and make sure to tick the "Suppress data from administrators as well as others" option. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".

Suppressing multiple revisions is achieved in a similar way:

  1. Repeat steps 1 and 2 as above;
  2. Then, tick "Yes" next to the properties you want to suppress, and make sure to tick the "Suppress data from administrators as well as others" option. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".

However, this only works if you want to suppress the same properties for all revisions involved. If, for instance, you need to suppress a certain property (e.g. text) of multiple revisions and an additional property (edit summary) in just one of them, you can do that in two steps:

  1. Select the relevant revisions and suppress their properties (text) as needed;
  2. Then, select the remaining revision, tick both the text and the edit summary options and proceed as usual.

This method allows you to perform the suppression in just two actions. Of course, it is possible to suppress the relevant revisions one by one, but it takes much longer, produces numerous entries in the suppression log and is harder to undo.

Suppressing current revisions


If you need to suppress certain properties of a current page revision (edit summary or user name/IP address):

  1. Go to the history page (or press alt + shift + h on your keyboard);
  2. Tick the current revision and press "Show/hide selected revisions";
  3. Next, tick the property you need to suppress (or both of them) and make sure to tick the "Suppress data from administrators as well as others" option. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".

This method does not work if you need to suppress the text of the current revision, since MediaWiki is not able to only delete the current revision of a page. In such a situation:

  1. Edit the current revision, manually remove the text you want to suppress, and save your edit;
  2. Suppress that previous revision as usual, making sure to tick the "Hide revision text" option so that no diffs are visible for non-oversighters (see #Suppressing previous revisions).

Most of the time, this method is used to suppress IP addresses of registered Wikimedia Wikispecies contributors who made edits while being logged out; see #Hiding IP addresses for more details.


Suppression of log entries normally does not happen on its own and is usually an addition to file or page suppressions. It is used to remove all sorts of data from all kind of logs, but its most popular usage is to suppress upload and (un)deletion logs of previously suppressed files so that they cannot be found outside of Wikispecies.

To suppress upload and (un)deletion log entries for a file:

  1. Go to Special:Log and paste the file name into the "Target" field;
  2. Tick all entries and press "Show/hide selected log entries";
  3. Depending on the issue, tick the appropriate properties (action and target, edit summary or username/IP address);
  4. Make sure to tick "Suppress data from administrators as well as others"; add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".

Hiding IP addresses


This is possibly the most common example of text-related suppressions performed here on Wikispecies. However, the general rule is that we do not suppress IP addresses of users if they don't request it personally, simply because some users are OK with their IP addresses being visible (for instance if they are dynamically assigned, ie. change often).

If a contributor accidentally edited a page while being logged out:

  1. Go to the history page (or press alt + shift + h on your keyboard);
  2. Select the relevant revision(s) and press "Show/hide selected revisions";
  3. Tick the "Hide editor's username/IP address" option and make sure to tick the "Suppress data from administrators as well as others" option. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision".

However, if the edit was made to a discussion page and contains a signature with the IP address inside the revision text, you'll need to suppress it, too:

  1. If the user logged in again and changed their signature, this can be achieved by ticking the "Hide revision text" option as in step 3 above;
  2. If the user did not yet change their signature, you need to do it for them. After saving the edit, perform all steps as above; in step 3, tick both the "Hide revision text" and "Hide editor's username/IP address" options so that you suppress both properties in one action.

This way, you not only suppress the IP address from the history page, but also make the diff between the two revisions (one with the IP address, the other with the regular user name) visible only to oversighters.

Abuse filter actions


Occasionally, some edits performed by accidentally logged out editors are caught by our abuse filter rules, which records them in the abuse log for everyone to see. Since the log is part of the AbuseFilter extension and not of the MediaWiki software itself, hiding (not suppressing) its entries is a bit different than usual.

To hide an IP address from an abuse log entry:

  1. At the abuse log page, click on "adjust visibility" in (details | examine | adjust visibility) next to the relevant log entry;
  2. Add a reason for your action in the "Reason:" field, make sure to tick the "Hide this entry from public view" option and press "Submit".

Unlike the regular log entries, it isn't possible to perform per-property hides on abuse log entries (for instance to hide only the IP address while leaving the target page and filter number public); you can only hide the entire entry.

Hiding users


Since MediaWiki 1.18, it is possible to entirely hide a user name on a wiki. This is especially useful when dealing with user names that leak non-public personal information or are insulting or harassing someone.

To hide a user, go to their block page (directly from a log, page history, or through their user page):

  1. On the block page, set the expiry time to "indefinite" and add a reason for your action in the "Reason:" field;
  2. Make sure to tick the "Hide username from edits and lists" option, tick other options as necessary, and press "Block this user";
  3. Next, confirm the block by ticking the "Confirm block" option and press "Block this user" again.

Ticking the "Hide username from edits and lists" option makes your block part of the suppression log and removes the user name from all kinds of automated logs as well as file pages, history pages, deleted contributions and recent changes.

Reverting suppressions


All actions performed through MediaWiki, including suppressions, are reversible. With a few exceptions, all actions can be reverted directly from the suppression log:

  1. For file- and page-suppressions, just click on the (change visibility) link and untick the options you want to unsuppress. Add a reason for the action in the "Other/additional reason:" field and press "Apply to selected revision";
  2. For blocks with the "Hide username from edits and lists" option set on, go to list of blocked users and paste the user name into the "IP address or username:" field;
  3. Click on "change block" in (unblock | change block), and add a reason for the action in the "Reason:" field. Untick the hiding option and press "Re-block the user with these settings".

If you mistakenly suppressed an action caught by an abuse filter rule, reverting yourself requires one more step than that:

  1. At the suppression log page, click on the event link (it will look similar to Special:AbuseLog/123456);
  2. Next, click on "adjust visibility" in (details | examine | adjust visibility) in the details box;
  3. Enter a reason for your action, untick the "Hide this entry from public view" option and press "Submit".

Communicating suppressions


Wikimedia Wikispecies oversighters have developed a habit of informing one another about their actions. This provides a possibility for immediate peer review of suppressions (as opposed to finding out about them weeks after they were made) and enables the rest of the team to stay in the loop as well as to comment on recent actions whenever necessary.

The principal mean of communication between oversighters is the oversight-Wikispecies mailing list, to which we all are subscribed. There is no need to go into extreme detail, as each of us can see what exactly was suppressed; a short description of what you did, why you did it and—if applicable—what errors you encountered (so that we can keep them in mind or report them to Phabricator) is just fine. As always, the mailing list archives are kept on a Wikimedia server, but the e-mails are forwarded to various boxes, so it is generally prudent not to include the information you suppressed inside the message itself and use links instead.

Updating statistics


Since November 2012, following the example of the English Wikipedia Audit Subcommittee, we have been keeping rolling six month statistics of oversighters' activity here on Wikispecies in order to give the community some sort of overview and increase the transparency of our actions.

As of June 2024, the statistics are manually compiled by odder (talkcontribsblock logall projects) at the beginning of each month by taking the data from the suppression log. For the purpose of these statistics, one action equals one log entry and does not refer to revisions, users, files or logs, since one action can affect multiple items (log entries, page or file revisions) at once. As a general rule, actions performed by Wikimedia Foundation staff (including developers) and stewards are not included there.

Getting help


Getting help with suppression-related issues isn't exactly easy. Due to the very nature of our actions, there is no public forum to discuss them, and their relatively small scope makes it unreasonable to have a private wiki; therefore, different tools are used.

For non-urgent matters, the best way to get help or receive feedback is to use the mailing list. When the request you are handling requires immediate action, the fastest way to get help is to look for other oversighters on the IRC channel #wikimedia-Wikispecies on Freenode (join via WebChat) and contact them privately. If none are available, you might want to consult oversighters from other Wikimedia projects at #wikimedia-privacy — please note that this channel is private and requires invitation or adding to its access list; contact Barras, DerHexer, guillom or Trijnstel to be added.

Whenever suppressing potentially illegal content, it is preferred to check global contributions of the user involved; use the GUC tool for that. If the user vandalised on a different project or is blocked elsewhere, contact the stewards on #wikimedia-stewards (WebChat) and request help by posting @steward + your request to the channel, and ask for the account to be locked. However, please don't post any abusive username in the channel but open a private query with the available steward. This way, the user will be signed off from all current sessions and won't be able to log in to the account again (details).

Due to the effect that suppression has on the visibility of data, all requests have to be analysed very carefully. It is usually advised to consult the oversight policy before taking any action. Our experience, however, tells us that this process can by simplified by adhering to a few rough slogans:

  1. Don't be afraid to deny requests. As mentioned above, the effects of suppressing data are severe, since there are currently only about 50 users with the suppressionlog user right on Wikispecies (including stewards and Wikimedia Foundation employees). Hence, some of the requests (mostly related to removal of insults and swearwords) are better served with regular revision deletion, e.g. without ticking the "Suppress data from administrators as well as others" option. However, our general rule is…
  2. Better be safe than sorry. None of us are professional lawyers (and even if we were, we could not act in professional capacity on a Wikimedia wiki), so all actions we take are based on experience, intuition, personal impressions and opinions. When it comes to potentially illegal content, it is therefore better to act preemptively than not to. For non-urgent issues, you might want to try consulting other oversighters first, but if your instinct tells you to act, just go ahead and remember that…
  3. Nothing is irreversible. However trivially this sounds, MediaWiki is designed so that nothing you do can cause irreversible damage. If you suppressed a log entry, file, revision or property of a revision (edit summary, user name/IP address or revision text), go ahead and revert your actions.

Contacting Wikimedia Foundation


On rare occasions, you may find yourself requiring the advice or assistance of Wikimedia Foundation employees.



If the situation involves a threat of harm to life, limb or property, immediately e-mail This address is monitored 24/7 by a team from the Foundation; they will acknowledge receipt of your message and ask any follow-up questions.

Child protection/illegal content


If the suppressions you performed are related to possibly illegal content, make sure to e-mail straight away. This way, the Support and Safety team can assess the situation and progress with their internal procedures. Don't worry about time zones, as this address is also monitored 24/7. If you're informing the other oversighters about your actions, just add this address to the CC field of your message.

General advice


If the situation does not involve illegal content or a threat of harm to life, limb or property, you can try to contact the following members of the Support and Safety team for advice or assistance:

  1. Begin by sending an e-mail to James Alexander at;
  2. If you don't get a fairly immediate response, e-mail Maggie Dennis at and CC

Reporting bugs


As all software, MediaWiki has the tendency of containing bugs. Unfortunately, even the revision deletion functionality that we use in our work isn't exactly bug-free! If you encounter a bug when trying to suppress data, please file a new report (see manual), but before you do so, consult the full list of open revision deletion bugs to check if the problem hasn't been reported already. Some of the bugs contain comments describing currently used workarounds which you might consider helpful for your work.

In case of software issues directly leaking personal information, it might be better to submit your bug with the security level set to Software security bug; in that case, feel free to CC other oversighters or describe the problem at the mailing list (since security bugs are not publicly accessible).

See also