ArchiveBox Exporter supports two different modes of operation:


Allowlist: Won't archive pages by default; you need to specify domains or regexes to archive

Blocklist: Will archive every page by default; you can specify domains to ignore

No matter which mode you choose, how you add domains or regexes stays the same.
To add domains to your allowlist/blocklist, open the extension from your browser's toolbar. From here, you can see or modify your list:

Domains
You can add full domains (e.g. example.com) or domain wildcards (e.g. *.example.com) to the list.
Regexes
You can also add regexes to test full URLs against, for more flexibility. To add a regex, toggle the Regex? checkbox before you add the entry. For example, if you wanted to automatically archive all Wikipedia wiki pages (all pages under https://en.wikipedia.org/wiki), you could add a regex like this:
https?:\/\/en\.wikipedia\.org\/wiki\/.+

Regexes are evaluated as case-insensitive (there may be an option to change this in the future, though!)