No idea and no idea. See if something is here : https://addons.mozilla.org/en-US/firefox/extensions/ Do Copy/Paste your Search Word to avoid frustration.

Mozilla only ok's Extensions submitted by Developers to be used with Firefox. They ok them only and give the Developer a web page to distribute their Extension from. This in no means that Firefox Support does the Developers Support when their page has a Support link and a contact Link.

Please let us know if this solved your issue or if need further assistance.

The Firefox Master Password only protects the Password Manager from access without the proper password. Not the whole profile.

As to your profile, only someone with access to your computer user account can access the profile.

You need to protect your Windows user account with a password and use a guest account to be used by other. Using an extension to protect your profile if such an extension would still be available can easily be bypassed by starting Firefox in Safe Mode by holding down the Shift key while starting Firefox.