Thanks for the review.

2) For export, you can go into the options, select "text" in the "view mode" drop-down list and copy/past the rules into a file.
For import, copy the rules from your file into the text field and click on the "save" button

3) For the whitelisting, you can also use the text mode in the options.
For example this rule will allow everything for the website domain.com:
domain.com * yes yes yes

5) Actually, websocket requests are treated as XMLHttpRequest (XHR) and the iframes as frame. I may add options to block globally ping and content-security-policy-reports requests.

badge counter and dark theme are good ideas. i'll make these options for the next version.

edit: i added a github repository