Ark 0.12 fixes a bug in Ark 0.11 where I’d mixed up some options so “don’t save” actually meant “overwrite”. Oops?
In 0.11 I added the code to get the current file size from the FireFox cache, and like FireFox, where I stole it from, it chokes on URLs with a # fragment identifier. This is presumably because only the http://example.com/index.php part of http://example.com/index.php#fragment is a document.
Ark just strips the fragment off now, since it shouldn’t be used in archive filenames anyway.
Lastly, I noticed that FireFox wasn’t picking a default extension for text/plain files, which is probably the Right Way. But I wanted .txt, so there you go. (Being the sole user of my software really makes it easy to bow to consumer demand.)