Settings · Table Rules, at three levels
Every rule the table plays by is set once for your account, and a campaign or an encounter can change any of them. A row shows the value in effect and whose it is. A change made lower down offers to be used higher up, and can be told to stop offering. Drawn in the app's Brass & Rust light scheme, the default.
Settings → Customize Game Rules
The account's rules
The sub-page he asked for, drawn like the Settings panel draws its rows: a label and a switch on the ground, a gray block where a row opens another page. Nothing here says whose it is, because everything here is the account's.
Campaign → Customize Game Rules
The campaign changes two
The same rows inside the campaign. The small line under a name says whose value is showing: Account, or Thornwood where this campaign set it. Every switch is live. Flip a Thornwood row back to what the account has and it is the account's again; there is nothing else to clear. Use for Account opens the sheet on the right for the two rows Thornwood changed.
Encounter, right after a change
The offer to use it higher up
The switch already flipped for this encounter before the sheet appeared; nothing waits on it. The two quiet lines are his, one per target, and each silences that offer for good. The two buttons under the rows do the same job on demand, for the rows this encounter changed.