Both layers: the server's _TEST_LOAD_MAX and the PWA's
TEST_ITERATIONS_MAX plus the two input max attributes. The value stays
inside 2^53-1 (the JavaScript safe-integer range), so the counters and the
progress display survive the JSON/JS round trip exactly; the practical
ceiling is the run duration (50 ms/iteration ~1.6 years at the cap).
The server's range error names the new cap automatically. The frontend
tests read the cap from index.html instead of stubbing a literal, and
clamp at it (above the cap, exactly at it, and the input max).
Docs: api.md, test-scripts.md, help EN/RU, the CHANGELOG (folded into the
unreleased 3.38.0) and the AGENTS notes. sw cache simple-v479.
1061 Python + 1071 frontend.