Detecting library/prerequisite mods

[allanonmage]

Is your feature request related to a problem? Please describe.
When building a modpack, library or prerequisite mods (also weirdly called dependencies sometimes), are not always called out, so you have to launch, track down, and add to the modpack.

Describe the solution you'd like
If there are any APIs aside from launching a modpack, please consult them and advise the users of prerequisite mods.

Describe alternatives you've considered
Reading the mod page, manually launching and reading the log.

Additional context
Probably something else that Modrinth could offer as a feature that Curseforge doesn't is an API to do this sort of thing. I'm not sure if either modloader does this.