Guide on Browser Extension (Portable with Ubuntu/chrome)

[Kayi1500]

Needs to inform the user that if they choose the portable installation, they should change the "path" in org.jabref.jabref.json to point to where the portable was downloaded. So for instance, if the portable edition was downloaded to "/home/user/Downloads/JabRef-5.3-portable_linux/JabRef" then one would have to change the path in org.jabref.jabref.json to "/home/user/Downloads/JabRef-5.3-portable_linux/JabRef/lib/jabrefHost.py"

[tobiasdiez]

Good suggestion. Could you prepare these changes by editing https://github.com/JabRef/user-documentation/blob/master/en/collect/jabref-browser-extension.md and open a PR? Thanks!