Unfortunately the forum search feature was taken down a while ago. So no there is no on site way to search.
It was taken down because it didn't work properly. There may be plans to try to implement it again eventually, but the site only has one permanent programmer currently, so things that are not high priority can take a while to get any updates.
From this Is there not a way to search the forums?, tips on using Google to search Subeta.
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One permanent programmer
Aren't all staff literally paid unlike on Marapets? Why couldn't they hire another dev?
Staff being paid is part of why they can't hire another dev--because Subeta doesn't make enough to afford a full-time dev who'd be getting a fair market salary. The site has a shoestring budget and Keith (the founder/owner) has expressed wanting to make sure that any work done for the site is compensated fairly.
Plus, Subeta's code is, from what I understand, very particular. I think I've read somewhere that it's difficult to contract work out because any dev who's hired would need to be effectively trained on the code before they could begin actually working on projects/fixes.