Well, I finally gave up looking for a solution -- maybe we'll find one after Mojave hits its final release, but it obviously won't be something that it easily used on older versions of Mac OS X / OS X / macOS.
So I made an alternative to Marc Wilson’s idea (above) and created a shell script which can either output a full list of all of the version numbers and their “friendly names” or will allow you to search for a specific name, for example, if you just want to know which version was called “Yosemite”.
You can find my script here:
I’ll leave the question open in case we do find a solution that doesn’t require an external script.
Update (over a year later)
Apple now maintains a web page with all of the names and corresponding numbers: https://support.apple.com/en-us/HT201260
You can get the list using this:
(echo "<table>" ; curl -sfLS "https://support.apple.com/en-us/HT201260" \
| tidy --tidy-mark no --char-encoding utf8 --wrap 0 --show-errors 0 --show-warnings no --clean yes --force-output yes --output-xhtml yes --quiet yes \
| sed -e '1,/<table/d; /<\/table>/,$d' -e 's#<br />##g' ; echo "</table>" ) \
| lynx -dump -nomargins -width='10000' -assume_charset=UTF-8 -pseudo_inlines -stdin -nonumbers -nolist
Will give this output:
macOS Latest version
macOS Catalina 10.15.2
macOS Mojave 10.14.6
macOS High Sierra 10.13.6
macOS Sierra 10.12.6
OS X El Capitan 10.11.6
OS X Yosemite 10.10.5
OS X Mavericks 10.9.5
OS X Mountain Lion 10.8.5
OS X Lion 10.7.5
Mac OS X Snow Leopard 10.6.8
Mac OS X Leopard 10.5.8
Mac OS X Tiger 10.4.11
Mac OS X Panther 10.3.9
Mac OS X Jaguar 10.2.8
Mac OS X Puma 10.1.5
Mac OS X Cheetah 10.0.4
Then again, Apple isn’t great about keeping documentation online, so it may be gone in a year or two.