This looks amazing!
In the past I've built a similar tool, where I needed the issues available offline so that I can work efficiently with crappy mobile internet on the go. [1]
But after a while I decided that it's easier to have a Browser Extension in place that caches the issues in the extension's storage and that are usable offline, too. [2]
My tools are pretty minimalistic and definitely not as polished compared to this! Will definitely give it a try!
What kind of format is the tool using for the issue cache? Are they stored in markdown? Are issues cached per-remote, too? Aka say github+private gitlab is pulled altogether?