'What is the {# .. #} comment syntax from?

I saw {# ... #} syntax used to comment out things in an HTML template. This is, as far as I know, not a part of "vanilla" HTML. What is this syntax from and in what contexts is it valid?

[Edit] Follow-up question. How would I google for the answer to this? I tried putting the syntax in quotes but that did not work.



Solution 1:[1]

Looks like a comment in Jinja templating engine https://jinja.palletsprojects.com

As seen here: https://jinja.palletsprojects.com/en/3.0.x/templates/#comments

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Source: Stack Overflow

Solution Source
Solution 1 Mike Irving