Returns a daily merged pull request series for your team (GitHub and GitLab combined), for the whole startDate to endDate range in one call. Without groupBy, returns the team's daily total (one row per UTC calendar day). With groupBy=department, returns one row per day and department. Each merged PR counts toward the department the author belonged to on the day it merged (primary department only), so a department transfer in the middle of the range splits correctly by day. Totals match GET /v2/api/billing/users/vcs-prs for the same dates. Authors who do not belong to any department are grouped under departmentId=null, departmentName="Unassigned" rather than dropped, so grouped totals still add up to the ungrouped total. departmentId limits the result to that department's subtree (includeDescendants=true) or that department alone (false, the default); the Unassigned group is excluded whenever departmentId is set. At most 35 days per request. The response has no commits field. teamId names the team to read, as on every PR Health endpoint; without it, the API key's team is used, else the signed-in user's first team.