Web Blocker & Timer od cDivus

Features:

Daily Time Limits: Set custom time allowances for specific websites and keywords.

Scheduling: Enforce modes automatically. Define custom active time and days to automate your blocks.

Custom Block Pages: Personalize your block screen by uploading your own static HTML files.

Usage Notes:

Local Files: To allow Web Blocker & Timer to manage HTML pages loaded directly from your storage, go to your browser's extension manager, find "Web Blocker & Timer," click "Details," and toggle on "Allow access to file URLs."

Incognito / Private Browsing: To enforce focus modes during private browsing, you must manually toggle "Allow in Incognito/Private windows" inside the extension settings details.

More at https://github.com/cDivus/Web-Blocker.