The notice by Mozilla is misleading (I have noticed it too).
The permissions use in FoxyTab are:
activeTab: To access Active Tab
clipboardWrite: To save to Clipboard (like copy URLs)
contextMenus: To make context-menus
notifications: To make notification (bottom of the screen)
tabs: To access Tab Data
webRequest & <all_urls>: New in v2.8, this is used to get the IP of the page loaded into the Tab for the Copy IP menu. That is all, no data is sent or stored. The IP comes from internal Firefox API in webRequest. It is not queried from a remote source. This feature is in preparation for a feature to show Country Flags in future.
IMHO, the All Browsing Data notice is misleading in this case, but that is a general notice since the same permission can be used for more extensive purposes.