Updated README

README.md

 
 ## Installation
 
-* Download or clone this repository
-* In Chrome, go to chrome://extensions (or Window menu -> Extensions, etc.)
-* Enable Developer Mode by clicking the toggle switch at the top right
-* Click the “Load Unpacked” button at the top left
-* Select the AlwaysKillSticky/chrome folder
+### Chrome/Vivaldi/Opera
 
-AlwaysKillSticky should now be installed!
+* [Download the latest release](https://wiki.obormot.net/Main/AlwaysKillSticky), or build from source (see below).
+* Unzip the package.
+* Go to `chrome://extensions` (Chrome), `vivaldi://extensions` (Vivaldi), or `about://extensions` (Opera) in the URL bar.
+* Enable Developer Mode by clicking the toggle switch (Chrome) / checkbox (Vivaldi) / button (Opera).
+* Click the “Load Unpacked” (or “Load Unpacked Extension”) button.
+* Select the AlwaysKillSticky-chrome folder.
 
-However, stickies will not be killed yet; you must now add some URLs to the **matching patterns** list (or, switch to **whitelist mode**); see **Usage**, below.
+### Firefox
+
+* [Download the latest release](https://wiki.obormot.net/Main/AlwaysKillSticky), or build from source (see below).
+* Unzip the package.
+* Go to `about:debugging` in the URL bar.
+* Click the “Load Temporary Add-on…” button.
+* Select the AlwaysKillSticky-firefox folder.
+
+### Building from source
+
+You can build the extension from source, using the provided `build.sh` script, passing the argument `chrome` (for Chrome, Opera, Vivaldi, etc.) or `firefox` (for Firefox & other Gecko-based browsers).
+
+### Post-installation
+
+If you follow the above instructions, AlwaysKillSticky should now be installed!
+
+Stickies will not be killed yet; you must now add some URLs to the **matching patterns** list (or, switch to **whitelist mode**); see **Usage**, below.
 
 ## Usage
 
 Open the AlwaysKillSticky options window (either by clicking on the AlwaysKillSticky icon in your toolbar, or by going to your Extensions page, clicking “Details”, then clicking “Extension options”).
 
-AlwaysKillSticky can work in either of two modes: **blacklist mode** and **whitelist mode**. (You can switch modes at any time.)
-
-### Blacklist mode
+AlwaysKillSticky can work in either two modes: **blacklist mode** and **whitelist mode**.
 
 In **blacklist mode** (the default), stickies will *only* be killed if:
 
 * the page URL matches one of the patterns in the **matching patterns** list, *and*;
 * the page does *not* match any of the patterns in the **exclusion patterns** list.
 
-### Whitelist mode
+Conversely, in **whitelist mode**, the matching patterns list is *ignored*. Stickies are *always* killed, *unless* the page matches one of the patterns in the exclusion patterns list.
 
-In **whitelist mode**, *the matching patterns list is ignored*. Stickies are *always* killed, *unless* the page matches one of the patterns in the **exclusion patterns** list.
+You can switch between blacklist mode and whitelist mode at any time.
 
 ## License