I don't think there is any way to donate bitcoin to the development of tiddlywiki in general. Jeremy (the guy who created TiddlyWiki) may use bitcoin, but if he does I haven't seen anything about it.
Individual developer people may take donations, but I am not aware of anyone other than
Eric Shulman and I do not know if he takes bitcoin or not (he maintains tiddlywiki classic, and is writing a book about tiddlywiki, and makes neat stuff).
I make stuff for tiddlywiki and try to maintain a
reference site that has
stuff (I am so very eloquent).
Recently I have been waffling about if I should ask for/accept donations for the things I make or not. I do like being able to eat and pay rent, but it seems weird to ask for something in return for things I do anyway.
I am actually very curious how people feel about this, and if anyone else is asking for or accepting donations for work they do.