Obviously, the “swoosh” is an optional design feature.
It has to be “high contrast” and non-shiny.
The braille is typically the same color as the background so it is less obvious to sighted people, but there’s no reason it couldn’t be the same color as the raised letter if necessary.
Other specs include certain sans serif fonts such as Helvetica, Futura, Arial, or Lucida Sans.
Text must be all uppercase with no italics or script.
Minimum text size is 5/8", max is 2". Min 1/8" between letters.
On signs which designate permanent rooms and spaces, tactile characters must be accompanied by Grade 2 Braille, a series of contractions that forms a shorthand version of braille. Braille must be raised a minimum of 0.025" and a maximum of 0.037". Braille must be located below the corresponding text. If the text is more than one line, the braille can be located below the entire text. Also, there must be at least 3/8" between the braille and the nearest tactile characters.
This is a really good spec sheet …