# manuals
ronn(1)     ronn.1.ronn
ronn(5)     ronn.5.ronn
ronn(7)     ronn.7.ronn

# external manuals
roff(7)     https://man7.org/linux/man-pages/man7/roff.7.html
grep(1)     https://man7.org/linux/man-pages/man1/grep.1.html
groff(1)    https://man7.org/linux/man-pages/man1/groff.1.html
sh(1)       https://man7.org/linux/man-pages/man1/sh.1p.html
test(1)     https://man7.org/linux/man-pages/man1/test.1.html
fork(2)     https://man7.org/linux/man-pages/man2/fork.2.html
man(1)      https://man7.org/linux/man-pages/man1/man.1.html
markdown(7) https://daringfireball.net/projects/markdown/syntax
manpages(5) https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man5/manpages.5.html