The requirements key in the metadata.json file is a list of external requirements for the module in the following format:

"requirements": [ {“name”: “pe”, “version_requirement”: “5.x”}]

name is the name of the requirement, for example "pe" or "puppet". version_requirement can be a semver (http://semver.org) version range, similar to dependencies.

Again, you can check the metadata.json file for validity afterwards using the new PDK command, as follows:

$ pdk validate metadata