Convert inline frontmatter to YAML

I thought I saw somwhere a tool or a plugin to convert inline frontmatter to YAML - but now I can’t seem to find it.

Is anyone aware of such a tool (or am I going crazy)?

If such a tool does not exist, is anyone aware of an elegant solution for this? I need to use my Obsidian files outside Obsidian, in a tool that does not recognise inline/“Dataview” frontmatter declarations.

This person used a tool called “Markdown Janitor”: