The way we pronounce English (pretty hard) Leader and Leather sound the same. But here, however, it's just about the affinity of the letters and the character it invokes. If you look at the comments of my first theme “Black Leader” you will find the real explanation of this title.

From the Firefox Settings menu, "General" tab / "Language and Appearance" / "Website Appearance" / select the "dark" option.

I might try this, but not in a short period of time.