I added ability to do blocking and made the "management" and "declarativeNetRequestFeedback" permissions optional, requested via a button on the popup page. While declarativeNetRequestFeedback works when you install it manually, the store version tells you the permissions are there, but chrome.declarativeNetRequest.onRuleMatchedDebug is undefined, so unfortunately, the store version can't count the number of requests. Blocking still works though, just you don't get any feedback about what's blocked.
I think this is still useful to be able to block extensions, so I'll keep carrying 2 versions, 1 for the store with limited functionaly.
Violation reference ID: Yellow Zinc Violation: Description provided is insufficient to understand the functionality of the item.