Download the full installer from; Download Firefox For All languages And Systems {web link}

If you don't want to use its default settings, use the manual option.

1. Drag the XPI file from the desktop into the Firefox browser window. 2. Use File > Open File thru the Menu bar, Or {Alt - F, then O} to get the Open File menu in Windows Explorer.

the-edmeister said

1. Drag the XPI file from the desktop into the Firefox browser window. 2. Use File > Open File thru the Menu bar, Or {Alt - F, then O} to get the Open File menu in Windows Explorer.

Thanks but i want to do it from C codes, not manually.

Can anyone help pls?

See:

• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options
• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options/Add-ons_in_the_enterprise
• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options/Sideloading_add-ons

cor-el said

See:

• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options
• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options/Add-ons_in_the_enterprise
• https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Alternative_distribution_options/Sideloading_add-ons

thank you cor-el, but add-ons installed by sideloading does not update automatically. it seems to be fully controlled by copied xpi file. is there any way to install a firefox managed xpi?

I think that would require to drop the XPI file in the extensions folder in the Firefox profile folder. You will have to edit the file name and make the first part the ID as defined in the manifest.json file (applications.gecko.id) like required with the other methods.