I think this might be as simple as Danbooru not using Tumblr blog IDs in it's artist identification, so those are being considered invalid. I may be mistaken though.
Posted under Bugs & Features
tamuraakemi said in forum #414953:
(also, certain users only have tumblr /blog/ IDs so the current method is a little weird)
user.tumblr.com redirects to tumblr.com/blog/user if they have their blog set to dashboard-only.
tamuraakemi said in forum #414953:
Seems like a good idea to support these. How do you get these URLs?
(also, certain users only have tumblr /blog/ IDs so the current method is a little weird)
guessed there should be something like Twitter ID in Tumblr ->
found Tumblr UUID (View Page Source in browser)->
the colon makes it look like Bluesky DID ->
replaced username in https://www.tumblr.com/blog/view/*username* with Tumblr UUID like replacing username (and domain) in https://bsky.app/profile/*username.domain* with Bluesky DID
That is how I found them.
Updated by eromelon
Looks like issue #5807, I didn't find know about the /blog/view links though. I'll update it with the info from this topic.