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.
@@ -30,6 +30,7 @@
# auto-import.
# .idea/artifacts
# .idea/compiler.xml
+# .idea/jarRepositories.xml
# .idea/modules.xml
# .idea/*.iml
# .idea/modules