Lifetime in seconds for the additional render assets a request opts into with
the with_har, with_warc, with_pprof_cpu, with_pprof_memory,
with_trace, with_navigator_video, and with_network_log fields. Default is
300. Set to 0 to disable additional assets entirely — the server then writes
none of them and omits the asset Link headers.
When a render produces these sidecars, the server writes each to a temporary
directory and advertises it on the response with a relative
Link: </assets?file=…>; rel="related" header. Clients fetch them from
GET /assets until they expire, after which the server reclaims them.
When signed URLs are configured (--server-signed-url), the asset links are
signed and their expires bound is set from this lifetime, capped at
--server-signed-url-max-age when that is smaller.