In an online version of draw.io you can enable extra plugins using their url like this https://www.draw.io/?p=svgdata
(svgdata
is the plugin id)
Is there a way to enable a plugin using Chrome app?
No.
In online version, the Plugins
is listed under extras.
In offline as well as in Chrome App, you can't see such an Option
Which means you can't add plugins in the offline version.
Remaining functionalities that you will miss in the offline version
May be because of issues with caching. If you add many plugins, each of them contains many files. Caching large number of files for offline usage will make the app worst and also consume more memory.
Anyway, you can submit a feature request here