In Facebook, the timestamp on a comment or post is a URL pointing to that comment or post. You can right-click one of those timestamps and "copy link address" or "copy link location" or similar, to get a link to the comment or post, which can be sent in an email, bookmarked, etc.
However, somewhere around late May, 2020, Facebook changed those URLs. Now when I right-click the timestamp and copy the URL for a facebook comment, there are two additional parameters added to the URL:
&__cft__[0]=...{a long string of mostly-alphanumeric characters)...
&__tn__=R]-R
What are they?
(The "tn" suggests something to do with a thumbnail, perhaps?)
The additional parameters don't seem to have any obvious effect. If I remove them, the link still works.
