Fetches the branches available to your supplier account live from the supplier, so you can pick which ones to save with Create Supplier Branch. Branches already saved in Zuper have branch_imported: true and their linked job account, and are always listed first; the rest are sorted by branch name in sort_order. SRS returns only the branches your SRS customer account can order from; ABC Supply lists the branches behind your Ship-To accounts and includes each branch's job_accounts, status and manager; QXO returns one entry per QXO account, prefixes branch_name with the account number and leaves job_accounts empty (use Get Branch Job Accounts). SRS and ABC Supply branch lists are reused for up to 12 hours, so a branch the supplier just added may take that long to appear. The provider must exist and be CONNECTED; otherwise the request fails with 404 (unknown provider) or 403 (not connected or reconnect required).