But anyways is there a way to install this plugin on there?
Unfortunately, no, not at this moment.
iirc, the macOS desktop client for Showdown is basically a self-contained Safari browser that loads the Showdown website. Showdex is a browser
WebExtension that needs to hook directly into the website, as well as the browser providing crucial
WebExtension APIs (like
chrome.runtime.onMessageExternal()) to load, read the battle state, etc.
Don't think that it's possible for Showdex to load into the desktop client without modifying the original source code (not to mention, it's not that easy getting Showdex on Safari either, which the homie
Christian took the
liberty of doing). We would need to fork the desktop client and release (& maintain) a separate version that includes Showdex. This is something that can be done (and we had a few people ask for this before), but at the moment, we got lots of bugs to fix, so we probably won't be looking into this anytime soon, sadly.
For the time being, using your browser is the only way to use Showdex. Hope that explains it :o