To be honest, this is quite an old plugin so thereās a chance it could be converted to a theme component now. I know some of the others have made that leap. Iām afraid I donāt know specifically if it would be possible with this one though.
It does add the topic contents to the load, so it canāt be done in a theme component. The data that it displays isnāt available without the plugin.
Does this also create a tooltip for topics referenced in text of posts? Also, would using the API of Discourse and loading the topic content on demand (thereby not requiring it to be a plugin, merely a JS-based enhancement) be a solution?