For some odd reason, Mozilla decides to rewrite URLs away from the addon's unique id to just its name.
This choice to provide "friendly" URLs also prevents them from allowing extension renames without also breaking URLs. There have been a number of extensions who either had a bad name choice or whose scope has changed enough that their original name doesn't make sense anymore. The extension is renamed, but the URLs stay broken.
The correct decision would be to have a unique id and name format like so:
Where the name could be anything arbitrary and the system wouldn't bother to look at it. Forum software tends to do this.
However, us web surfers have no simple way to learn the unique id of a mozilla extension to ensure that our URLs do not include the name.
- Visit the extension URL. For example https://addons.mozilla.org/en-US/firefox/addon/keywordurl-hack/
- View the source of the page.
- Search the source for
data-addonidand get that number
- In our example, the addon id is 457813.
- Remove the en-US
For our example, the URL would become https://addons.mozilla.org/firefox/addon/457813 with an optional trailing slash.