I’m not sure whether this will be useful for many others here, but it’s been something that I’ve been missing, so I wrote it up today in case it is of use to others:
I’ve created a GitHub Gist here to demonstrate using the Templater plugin to use GitHub.com’s API. The template will look up GitHub Issues across a number of repositories (defined by the user in the template), combine them into a searchable prompt, and insert a markdown link of the user’s selection:
Notes on creating an access token for the GitHub API are embedded in the code, here.