Basically, FB is expanding its tracking, allowing 1st party vs. their third party cookie tracking. I suspect the click-id query string is part of that rollout. This helps it get around things like Apple's new ITP (Intelligent Tracking Prevention). 2.0 in Safari.
https://www.inc.com/peter-roesler/facebook-to-allow-for-firs...
https://digiday.com/marketing/wtf-what-are-facebooks-first-p...
Basically, FB is expanding its tracking, allowing 1st party vs. their third party cookie tracking. I suspect the click-id query string is part of that rollout. This helps it get around things like Apple's new ITP (Intelligent Tracking Prevention). 2.0 in Safari.