Per suggestions at T273220#8665225 and T273220#8671856, the ext:StopForumSpam stopforumspam-is-blocked message should be updated to include the following external link / privacy text:
You are about to leave WIKI_SITE to visit EXTERNAL_SITE which may receive data from your device. Please check their respective privacy policies. Click here to continue on to EXTERNAL_SITE.
Change 897944 had a related patch set uploaded (by SBassett; author: SBassett):
[mediawiki/extensions/StopForumSpam@master] Update stopforumspam-is-blocked message with privacy language
As the WMF-Legal project tag was added to this task, some general information to avoid wrong expectations:
Please note that public tasks in Wikimedia Phabricator are in general not a place where to expect feedback from the Legal Team of the Wikimedia Foundation due to the scope of the team and/or nature of legal topics. See the project tag description.
Please see https://meta.wikimedia.org/wiki/Legal for when and how to contact the Legal Team. Thanks!
Change 897944 merged by jenkins-bot:
[mediawiki/extensions/StopForumSpam@master] Update stopforumspam-is-blocked message with privacy language