There is a bit of misunderstanding about permissions that web browser prompts for before installation of Ant Video downloader.
In order to use a portion of browser's application programming interface (API) an extension specifies in its manifest a keyword under "permissions" section. Once keyword is specified, web browser allows the extension to use API. It does not matter whether extension actually uses whole API or only part of it, the keyword must be present in extension's manifest file.
In turn, web browser notifies user about the fact that one or several permissions are required by extension without going deep into technical details. Web browser does not check how much API does extension actually use.
Ant Video downloader utilizes several permissions in order to function properly. Without those permissions AVD won't work at all, or will work in cumbersome manner. I do not want to expose much of AVD internals, but will try a few examples.
AVD uses so called "Access browser tabs" permission to check whether Ant Video downloader tab is already opened when you click AVD button. Without this permission AVD will always open a new Ant Video downloader tab (I'm not even sure if it can open a new tab without this permission). So without this permission we would have tons of messages from our users like "Guys, can't you do something with these new tabs, can't you just bring up the existing Ant Video downloader tab up instead of opening a new ones?".
AVD internally consists of several components that exchange data using browser internal storage. By default, storage limit is set to 5 Mb. When AVD is used, it stores more and more data in the internal storage. In the situation when there are several browser windows, each having several dozens of tabs, AVD can easily run into storage limit, and stop functioning after it. That's why we use "unlimitedStorage" permission. Don't worry: internal storage is cleared out when you launch web browser next time, so there is no wasting of disk space.
WebExtensions (and AVD is built using WebExtensions technology) are running sand-boxed and don't have access to whole computer, I don't know why do you think that or where did you hear that.
The last thing is that we submit AVD source code to Mozilla for reviewing, before AVD is made available on addons.mozilla.org it is passes review by Mozilla moderators. They check AVD source code for any backdoor/identity theft/tracking/My Bank and credit card/so on/so forth.
Regarding the info: we do not either collect or sell any personal or sensitive information of our users. Period.
More information on AVD and WebExtensions:
- Manifest file format: https://developer.chrome.com/apps/manifest
- What are extensions?: https://developer.mozilla.org/en-US/Add-ons/WebExtensions/What_are_WebExtensions
- About the new ant video downloader 3.0: https://support.ant.com/hc/en-us/articles/115005568983-ABOUT-THE-NEW-ANT-VIDEO-DOWNLOADER-3-0
Hope we made some things clear for now.
If you have any questions, do not hesitate to contact us.