Headroom test payloads (fetched/generated 2026-10-20 ~11:20 UTC+8). Full payloads and every compressed output are kept in the repo under runs/2026-10-20/tools/headroom/payloads/, not published here.
1. github_issues: GitHub REST API GET /repos/psf/requests/issues?state=all&per_page=100 (100 issues incl. PRs, all fields, bodies). 594797 bytes.
2. pypi_info: https://pypi.org/pypi/<name>/json for 100 popular packages, 'info' reduced to name, version, summary, license, requires_python, author, home_page, project_urls. 245381 bytes.
3. synthetic_logs: 2,000 JSON log objects (ts, level, service, msg, latency_ms, request_id), Python random seed 11, one FATAL at index 1337: service billing, 'ledger write failed: disk quota exceeded on /var/lib/ledger (errno 122)', req-424242. 280879 bytes.
4. wiki_search: Wikipedia API list=search for 'python', 300 results (ns, title, pageid, size, wordcount, snippet, timestamp). 112622 bytes. For C3 we added 'java', 'linux' and 'database' searches (300 each) to reach 100K tokens.

--- Excerpt: first 600 characters of Headroom's output for synthetic_logs (default compress()) ---
[2000]{latency_ms:int,level:string,msg:string,request_id:string,service:string,ts:string}
465,INFO,job started,req-632510,search,2026-10-20T08:00:00Z
826,DEBUG,cache hit,req-636775,worker,2026-10-20T08:00:03Z
99,INFO,cache hit,req-568286,search,2026-10-20T08:00:06Z
554,INFO,request handled,req-948973,worker,2026-10-20T08:00:09Z
466,INFO,job started,req-785687,search,2026-10-20T08:00:12Z
18,DEBUG,job finished,req-972102,worker,2026-10-20T08:00:15Z
39,WARN,request handled,req-299447,api,2026-10-20T08:00:18Z
799,INFO,request handled,req-586470,search,2026-10-20T08:00:21Z
865,INFO,job finished,req

--- Excerpt: the FATAL row in Headroom's output ---
0,FATAL,ledger write failed: disk quota exceeded on /var/lib/ledger (errno 122),req-424242,billing,2026-10-20T09:06:51Z

--- Excerpt: header + 2 rows of Headroom's output for wiki_search, one with a retrieval marker ---
[300]{ns:int,pageid:int,size:int,snippet:string,timestamp:string,title:string,wordcount:int}
0,23862,143579,"<span class=""searchmatch"">Python</span> is a high-level, general-purpose programming language that emphasizes code readability, simplicity, and ease-of-writing with the use of significant",2026-10-18T00:26:32Z,Python (programming language),11508
0,271890,24502,<<ccr:41cce983901a,html,290B>>,2026-10-16T21:27:44Z,Ball python,2547

--- github_issues and pypi_info: Headroom's output was byte-identical to the input (0% saved) ---
gh_issues.json True
pypi_info.json True