https://docs.atlassian.com/jira/REST/latest/#id162673

The current implementation allows for PUT, POST calls allow for application/json request for input parameters, for example:

{ "user" : ["admin"] } or
{ "group" : ["jira-developers"] }

The DELETE method, however, does not accept application/json, but you instead need to append the URL:

/rest/api/2/project/{projectKey}/role/{id}?user={username}
/rest/api/2/project/{projectKey}/role/{id}?group={groupname}

This behaviour is inconsistent between the methods. We should allow the DELETE method to also allow for application/json

(Also, there's no documentation example on how to make a DELETE call to projectroles. Users who attempt this may get confused)