[layer8]

These are called numerical contractions [0] and are fairly well-known, in particular i18n and a11y.

Another one that used to be well-known is s9y for Serendipity [1].

[0] https://en.wikipedia.org/wiki/Numeronym#Numerical_contractio...

[1] https://s9y.org/

[manmal]

I brought it up because GP had k18s.