What does “http://*/*”, “https://*/*” and “” mean in the context of Chrome extension’s permissions

• "<all_urls>": matches any URL that starts with a permitted scheme (http:, https:, file:, or ftp:).
• "http://*/*": Matches any URL that uses the http: scheme.
• "https://*/*": Matches any URL that uses the https: scheme.
• "*://*/*": Matches any URL that uses the https: or http: scheme.

These permissions are required if your Chrome extension wants to interact with the code running on pages.

Match patterns documentation