I currently have a chrome extension which adds a new button on the GMail Toolbar each time I open a message in GMail on a chrome tab. This is done currently using inboxSDK's (1) registerThreadViewHandler() and (2) registerMessageViewHandler()
Unfortunately, using inboxSDK library will make the extension call remote code which is disallowed in Manifest V3.
I would like to ask if there are other possible and sustainable ways to do this without inboxSDK.
Thank you very much.