Rest API - Metadata for Jira 5.2
Base path for the Rest API: Jira_Base_Url/rest/metadata/1.0
e.g. get the first 20 metadata for project JM (as project-admin): https://jira.atlassian.internal/rest/metadata/1.0/project/JM?includeHidden=true&startAt=0&maxResults=20