testing/cross_backend/default_secrets.ts view source
"test_bootstrap_token_for_cross_be" Fixed bootstrap token written to each backend's token_path before
spawn. The test binary reads + consumes this via its
*_BOOTSTRAP_TOKEN_PATH env var; the harness POSTs the same token to
/api/account/bootstrap to mint the keeper account. Any 32+ char
string works — the binary just compares bytes, no entropy required
for tests.