Bugzilla user from decade ago tashe user name but I can’t find anything else

Well, I suggest testing the emails you still have access to on the create account page. If an address is accepted, then presumably there is no account for that one. If all of your current email addresses are available, the old account may be associated with an obsolete address and you'll need to create a new one anyway.

https://bugzilla.mozilla.org/createaccount.cgi