Sugestion: Use a more user friendly name for the profile created during install

[calloatti]

Instead of this: (fabric-loader-1.15.2)

This: (Fabric-1.15.2)

[TheBrokenRail]

If you are going to make things title-case, why not remove the hyphen as well?

[haykam821]

It seems like this can't be changed without potentially causing duplicate installations as well. Perhaps something more reasonable, like the UUID that the launcher uses, can be used as a key instead?

[sfPlayer1]

We can actively handle duplicates though, potentially prompting the user for whether it should replace the existing entry or add a new one (Fabric 1.15.2 #2, Fabric 1.15.2 #3, ...)

[calloatti]

The name the user sees in the UI for an instance is the "name" property value, not the key for the instance in launcher_profiles.json

Mojang seems to use a guid for instance keys.

The fact that the Fabric installer uses the same value for "name" and the instance key may not be ideal, should probably do what the launcher itself does, generate a guid and use that as the instance key.

So there is no need to handle duplicate instance names, even the launcher does not check for that: