Vanilla moved all GUI elements to an atlas instead of using multiple files. Hearts are now added to the same atlas and don't require coloring on each render frame anymore. Resource pack creators will get an update about the exciting new system and the way it works in the next few days on the GitHub repository.
Developer information
Projects on Modrinth are automatically available through a Maven repository for use with JVM build tools such as Gradle.
maven { name = "Modrinth"; url = "https://api.modrinth.com/maven" }
