Since IntelliJ 2019.3 this file appeared in our git changes. It seems these are just cached information about remote repositories that are defined in Maven/Gradle.
In our IntelliJ projects where we are using Gradle, the file .idea/compiler.xml and files inside the .idea/artifacts folder are automatically generated by IntelliJ based on the Gradle build model. As these files are generated, they should be ignored in version control.