Link Properties Plus WE door Infocatcher

Provides extended link properties: size of linked file, last modified time, etc.

This is a fork of Extended Link Properties by Torisugari (now disabled).
Based on version 1.2.5 from forum.addonsmirror.net (saved page on web.archive.org).
Continuation of my old (unofficial) development: forum.mozilla-russia.org/viewtopic.php?pid=376740 (and following).

Source code and issues tracker:
https://github.com/Infocatcher/Link_Properties_Plus_WE
Classic full-featured version for Firefox 56 and older:
https://github.com/Infocatcher/Link_Properties_Plus