In addition to Aaron's helpful pointers, here are the timestamps (all in
UTC) I've found for when ACTRIAL started and ended, and when the permanent
restriction went into place:
ACTRIAL start: 2017-09-14 22:30:00 or thereabouts, ref the first post by
Kaldari in this archived thread from the ACTRIAL talk page
<https://en.wikipedia.org/wiki/Wikipedia_talk:Autoconfirmed_article_creation_trial/Archive_4#ACTRIAL_is_live>
.
ACTRIAL end: 2018-03-14 17:30:00 or thereabouts, based on the timestamp of
the first article created by a non-autoconfirmed user after ACTRIAL ended.
ACPERM start: 2018-04-27 00:00:00 or thereabouts, based on the timestamp in
T192455#4162881 <https://phabricator.wikimedia.org/T192455#4162881>.
You can also see the dates for these in this dashboard showing page
creations by non-autoconfirmed users on enwiki
<https://page-creation.wmflabs.org/#projects=enwiki/metrics=Daily%20Pages%20Created%20in%20the%20Main%20namespace%20(ns%3D0)%20by%20non-autoconfirmed%20users>
.
Cheers,
Morten