I added cache rule but it doesn't work

[platonische]

(http.request.uri contains “pantone.js”)
Eligible for cache
Browser TTL (optional)
Override origin
1 hour

I want to reduce browser ttl for some files

[cbrandt]

You cannot reduce time set by Cache-Control with Browser Cache TTL, only increase it.

You’d need to send a Cache-Control header from the origin for the file(s) you want with a smaller max-age instruction, then use Respect Existing Headers in your Cache Rule.

Documentation is a bit confusing, but this is what I understand.

Nevertheless, the value you set via Page Rule will be ignored if Cache-Control: max-age is higher. In other words, you can override to make browsers cache longer than Cloudflare’s edge [the time set by your origin’s Cache-Control] but not less.

(edit is mine, based on testing with different Cache-Control and Browser Cache TTL values)

Set Browser Cache TTL · Cloudflare Cache (CDN) docs