[berkes]

The search in thunderbird is terrible compared to what we are used to today. Same for k9 (now thunderbird for android?).

Not only is the UX a horror, its results rely on all sorts of technicalities. I, as a software engineer, can understand that a mail has to be downloaded in entirety locally in order to have it indexed and then show up in the results. And I understand that sub-sub directories aren't really a thing in IMAP, so searching this-dir-and-everything below is hard/impossible and so on.

But mostly the search algorithms are poor. So much so, that I often rely on (rip)grep to find mails. Or in a few occasions wrote a quick bash/python horror to push all my mail into a meilisearch instance and then use this search engine to get the lists and filters that I would expect thunderbird to have.

Yes. It's open source. So "go fix it" is a proper reply. But that doesn't make a complaint about the state of the search feature invalid.