Upcoming change to derpibooru.org:
> Some of our subdomains are being deprecated. Effective March 1, 2024, www.derpibooru.org and www.trixiebooru.org will redirect to their non-www counterparts. Read further / discuss here [ https://derpibooru.org/forums/meta/topics/deprecation-of-the-www-subdomains ].
AT says that "Subdomains...are entire sites":
https://wiki.archiveteam.org/index.php/List_of_websites_excluded_from_the_Wayback_Machine/Partial_exclusions

I'm guessing that these are exactly the same: www.derpibooru.org / derpibooru.org and www.trixiebooru.org / trixiebooru.org.

 >>/9399/
YT video yTG175TXR9k was deleted, in case that wasn't clear.
 >>/9400/
> Two spaces between here: -> <-
Nope, Endchan also does /\s\s+/\s/.