Adding Oauth tag as that is the closest I can find to one for the BotPasswords functionallity (please change if wrong)

There isn't an issue with BotPasswords or Pywikibot. None of the grants on that wiki have editallpages, so when using a BotPassword or OAuth you effectively don't have that right. A configuration change is required to add editallpages to one (or more) of the existing grants.

See $wgGrantPermissions.

Thanks @JJMC89 I'd missed that editallpages had been especially crafted for sewikimedia. I guess it can either be added to the editpage grant (or maybe the sewikimedia config might be simplified by now).

Quick note to self: Should be possible to add the following at about line 12421 of wmf-config/InitialiseSettings.php

# wgGrantPermissions @{
'wgGrantPermissions' => [
  'sewikimedia' => [
    'editpage' => [ 'editallpages' => true ], // T184981
  ],
],
# @} end of wgGrantPermissions

Probably more like '+sewikimedia', although even that might replace editpage instead of merging into it (if that's the case you'd have to add it in CommonSettings.php).

In T184981#3906465, @Tgr wrote:

Probably more like '+sewikimedia', although even that might replace editpage instead of merging into it (if that's the case you'd have to add it in CommonSettings.php).

I looked into the source of the extra right and found that neither it nor the extra user group are used anymore. I'll update the task description and submit a patch.

Thanks everyone for figuring out the source of this behaviour.

Change 404942 had a related patch set uploaded (by Lokal Profil; owner: Lokal Profil):
[operations/mediawiki-config@master] Drop the medlem user group and editallpages user right

https://gerrit.wikimedia.org/r/404942

This is approved according to our MediaWiki extension policy. https://se.wikimedia.org/wiki/Wikimedia:Mediawiki_Extension_Policy

Please do not forget to remove all users from that group. If you do not remove the users from the group previously, the result is that they'll still will hold the 'medlem' right in the shadows and will appear as such in Special:ListUsers. If there are many, you can get them removed from the group by manually issuing a SQL command. See example at T171682 (although there are more I filled but I can't find them atm).

In T184981#3915760, @MarcoAurelio wrote:

Please do not forget to remove all users from that group. If you do not remove the users from the group previously, the result is that they'll still will hold the 'medlem' right in the shadows and will appear as such in Special:ListUsers. If there are many, you can get them removed from the group by manually issuing a SQL command. See example at T171682 (although there are more I filled but I can't find them atm).

Thanks. I've now removed all of the members from that group.

I feel sorry you had to do all that by hand. MediaWiki core should offer a maintenance script to do this.

In T184981#3929208, @MarcoAurelio wrote:

I feel sorry you had to do all that by hand. MediaWiki core should offer a maintenance script to do this.

Not too bad since not too many. But for larger wikis a maintenance script would be good.
Is there anything else needed from the patch?

Left a couple of comments in the patch.

The patch looks good to me now. @Urbanecm can you have a look at it as well? Thanks.

Gentle ping about this patch @Urbanecm

Change 404942 merged by jenkins-bot:
[operations/mediawiki-config@master] Drop the medlem user group and editallpages user right

https://gerrit.wikimedia.org/r/404942

Mentioned in SAL (#wikimedia-operations) [2018-02-28T14:50:22Z] <zfilipin@tin> Synchronized wmf-config/InitialiseSettings.php: SWAT: [[gerrit:404942|Drop the medlem user group and editallpages user right (T184981)]] (duration: 00m 57s)