I made some tries this morning and it seems that it isn't yet possible. StewardBot gets his informations from the RC feed on #meta.wikimedia@irc.wikimedia.org and this feed doesn't mention yet the expiracy of the permission (My try with an expiracy of 1 day gives: [[Special:Log/rights]] rights * Linedwell * changed group membership for User:Linedwell@testwiki from (none) to autopatrolled: test forStewardBot update exactly the same log as a permanent permission change). When the RC feed will mention it, I will be able to submit a patch to allow StewardBot to take this value into account.

<StewardBot> Masti changed user rights for Luensu1959@lijwiki from sysop to sysop with the following comment: [[Special:Permalink/16996278]]

that really makes sense to look for expiration date of rights.
In the case above the right were still valid till 17:34, 25 July 2017 when I changed it
(change visibility) 18:40, 14 July 2017 Masti (talk | contribs | block) changed group membership for Luensu1959@lijwiki from administrator (temporary, until 17:34, 25 July 2017) to administrator (temporary, until 18:40, 14 July 2018) (Special:Permalink/16996278)

What I said at T164204#3225569 is still valid. Unfortunately I do not speak python so I cannot fix the code to support that. I'm not sure if @dungodung or other python-expert would like to look at the code at rTSTW tool-stewardbots and provide a fix?

As I said in T164204#3334618, the bot's code cannot be updated while the RC feed doesn't mention the expiration date of rights (the bot cannot guess it if the feed doesn't mention it). Once T167568 closed, we will be able to update the bot code.

@Linedwell @bd808 And what about switching to EventStreams? RCstream is being deprecated in favor of EventStreams. Maybe we should think on making a bot that could use that information? Does EventStreams display temporary rights changes? Regards.

event: message
id: [{"topic":"codfw.mediawiki.recentchange","partition":0,"offset":-1},{"topic":"eqiad.mediawiki.recentchange","partition":0,"offset":291979059}]
data: {"bot":false,"comment":"test T164204 on EventStream","id":10118494,"log_action":"rights","log_action_comment":"changed group membership for User:MarcoAurelio@testwiki from sysop to sysop, bot: test T164204 on EventStream","log_id":22786802,"log_params":{"newgroups":["sysop","bot"],"newmetadata":[{"expiry":null},{"expiry":"20170715205247"}],"oldgroups":["sysop"],"oldmetadata":[{"expiry":null}]},"log_type":"rights","meta":{"domain":"meta.wikimedia.org","dt":"2017-07-14T20:52:47+00:00","id":"644801ae-68d6-11e7-9531-141877613a1c","request_id":"efdf3b98-15a6-42c3-8290-5323d3bb9e37","schema_uri":"mediawiki/recentchange/1","topic":"eqiad.mediawiki.recentchange","uri":"https://meta.wikimedia.org/wiki/User:MarcoAurelio@testwiki","partition":0,"offset":291979058},"namespace":2,"server_name":"meta.wikimedia.org","server_script_path":"/w","server_url":"https://meta.wikimedia.org","timestamp":1500065567,"title":"User:MarcoAurelio@testwiki","type":"log","user":"MarcoAurelio","wiki":"metawiki"}

EventStream does display if rights are temporary or not, and if they were previously temporary or not as well.

EventStreams are likely to get a lot more love for feature enhancements than the private irc network. The core reason for this is that EventStreams are being actively developed by the Foundation to provide a data feed for other internal services like cache invalidation. The irc feed is used by a lot of tools developers and others, but it doesn't have an engaged owner/maintainer.

Change 374051 had a related patch set uploaded (by Melos; owner: Melos):
[labs/tools/stewardbots@master] Show user rights expiry in user rights notification message

https://gerrit.wikimedia.org/r/374051

Change 374051 merged by jenkins-bot:
[labs/tools/stewardbots@master] Show user rights expiry in user rights notification message

https://gerrit.wikimedia.org/r/374051

Tested again, looks good to me as well. I've updated the stewardbot public code.