This is a theme for the Developer Tools [CTRL/CMD + SHIFT + I].
Fork of https://github.com/mauricecruz/zero-base-themes.
The theme is a mix between Zero Dark Matrix for Dev Tools colors and Obsidian for the code highlighting.
Make sure you enabled custom UI themes by following these steps:
Open chrome://flags ▶ Enable Developer Tools experiments and click “Relaunch Now” at the bottom.
Open developer tools settings ▶ Experiments ▶ [✔] Allow custom UI themes.