Minecraft wiki entry for Version_manifest.json, associated text: The root tag.
 latest: The latest release and snapshot versions.
 release: The ID of the latest release version.
 snapshot: The ID of the latest snapshot version.
 versions: A list of versions available.
One of the version entries.
 id: The ID of this version.
 type: The type of this version; usually release or snapshot.
 url: The link to the <version id>.json for this version.
 time: A timestamp in ISO 8601 format of when the version files were last updated on the manifest.[verify]
 releaseTime: The release time of this version in ISO 8601 format.
 sha1 (v2 only): The SHA1 hash of the version and therefore the JSON file ID.
 complianceLevel (v2 only): If 0, the launcher warns the user about this version not being recent enough to support the latest player safety features. Its value is 1 otherwise.