The profiler features were not initially localized in Bug 1599774. This area is pretty deep in the UI, and is mostly geared towards Firefox engineers. I'm not sure it's worth localizing them, but perhaps it is? This bug can track the decision and implementation

I think those strings only show up in about:profiling ?

Opening the page today on a localized Firefox build feels odd because the UI switches between English and the locale of the build several times in the page. Trying to read the page from top to bottom, the language changes 8 times. It's not the best experience, but I don't think it has to block enabling the panel.

They also show up in the devtools panel, when the "custom" preset is used.