Double click your German nouns to know their Der-Die-Das.
You can also search manually from the extension's icon.

The extension uses the de.wiktionary.org REST api in order to get the articles.
Here is the source code: https://github.com/kamomil/DerDieDas/tree/ff
Please give positive reviews if you liked it and report bugs in github.
enjoy

Install

• License: Mozilla Public License 2.0
• Weekly downloads: 0
• Average daily users: 2
• Rating: 5/5 of 1 ratings
• Created: 2019-06-02 15:14:47
• Last updated: 2019-06-02 15:30:10
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/דרדס/
• API: {d3ba0da9-f431-4fea-a0b5-796eb7dcf132}