matthin [1] filed a deletion request for atlassian-stash [2]:

Stash has been renamed to Bitbucket Server, which already is an aur package named bitbucket-server.

Proof of rename - https://confluence.atlassian.com/bitbucketserver/bitbucket-rebrand- faq-779298912.html

[1] https://aur.archlinux.org/account/matthin/ [2] https://aur.archlinux.org/pkgbase/atlassian-stash/