Some "public facing" documentation would be useful, not so much so that we can have something in Documentation, but more to validate that how this works is appropriate. (It'll become part of the commit message!)

For example, this approach involves using the @(AndroidInstallModules) item group. Item groups can't be specified on the command line. Is this a problem? Is there an expectation to be able to specify modules on a msbuild /t:Install command line, or is editing the .csproj the preferred experience?

@jonpryor currently this new AndroidInstallModules is not very useful. Its the beginning of a much larger piece of work outlined in #4810 (comment). I can document the new ItemGroup, but users will currently have no use for it since we need to do allot of the other stuff on the list at #4810 (comment) to make it useful.

@jonpryor I had added the docs for the ItemGroup here https://github.com/xamarin/xamarin-android/pull/5327/files#diff-db5645f8a1e864de401ac4a261afe73af36e10043135012bebc8cacfeb3820d0R149. There isn't much more to say since uses can't use this feature yet unless they build a module completely manually (and process is not not documented).