@hawk GitLab has used a syntax for this for several years GitLab Multline Blockquote:
>>>
Multiquote starting here
line x
line y
line z
>>>
It can handle multiple levels (like a code-fence block). Support was recently added to comrak, and there is a markdown-it plugin as well markdown-it-glfm-multline-blockquote - npm. The spec file can be found at spec/fixtures/glfm-spec/multiline_blockquote.txt · main · GitLab.org / ruby / gems / GLFM Markdown · GitLab
