PostScript
PostScript is a programming language that is primarily used for creating and manipulating vector graphics. It is commonly used in printing and imaging applications.
Hello, world:
%!PS
/Helvetica 20 selectfont
70 700 moveto
(Hello world!) show
showpage
Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.