Yaml

See wp:YAML

I learned it when it was first introduced in 2001 so at that time it was known as "Yet Another Markup Language", however the acronym later became a recursive backcronym standing for "YAML Ain't Markup Language".

Used everywhere, such as Ansible, so refer to https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html as well