Editor Support
You are welcome to use any editor you like, however, many of the Myriad developers use IntelliJ IDEA. The build process uses Gradle (https://gradle.org/). The build script is configured with the Idea Plugin (https://docs.gradle.org/current/userguide/idea_plugin.html) to create an IntelliJ project structure. This is accomplished with the following command:
./gradlew idea // to open on a mac open myriad.ipr
If you are interested in using Eclipse, there is a plugin for that. Either send in a pull request, or send a message on the dev mail list that you would make use of it.