No catch, no account.
FrameCatcher is free
Every mode, every export, no sign-up and no limit on how much you use it.
What does cost something is keeping it online. That is a domain and the odd bill, and it is small. If FrameCatcher saved you an afternoon of scrubbing through footage, you are welcome to put something toward it. If you would rather not, use it anyway. That is the whole arrangement.
Ko-fiOne-off or monthly, with a note if you likePayPalIf you would rather just send it acrossPromptPayThai bank transfer or TrueMoney, nothing taken off
Where the money would go
The domain, and a server that is still there to handle the few videos a browser cannot open on its own. Nothing else. There is no company behind this and no one drawing a salary from it.
Does donating get me anything extra?
No, and that is deliberate. There is no tier, no unlock and no queue to skip, because everyone already has all of it. A donation is a thank-you, not a purchase.