One has to boggle at the seven (as of this post) people who picked "YAML" (let alone the poll's authors for including it; then again it's used to "script" / configure ansible, k18s, openshift, yadda yadda so I might could see maybe a smidgen of validity to that as a choice).
The cake is a lie.
The cake is a lie.
The cake is a lie.
If you look at Github actions, they are shell scripts where each command is stored as a list entry in a YAML file. I'm not sure why they didn't go with simple shell scripts, but it seems that about every one of these CI things starts out as "simple YAML file" and evolves into a shell script, except stored in YAML.
IIRC, storing scripts in an XML document indicating what interpreter to use for each snippet was patented by Microsoft years ago, but YAML might still be free to use ;-)