Try it: will a note read as YAML?

The 60 percent line test

    For the example: 3 of 4 non-blank lines read as YAML (75%), which is over the 60% line.

    The checker runs in your browser and sends nothing. It applies the line rule from sniff.rs: a non-blank line counts when it matches key: value or starts with - , except - [ ] and - [x] task items. Under 3 non-blank lines the share is 0. The sniffer also needs the text to parse as YAML, which this checker does not test.