Somewhat like a snowflake cut, but folded differently.
These are the instructions from an old fold and cut calendar by Jeffrey Cole.
Once the paper is folded you can cut whatever you please. The heart shape is made by cutting the outside edge line that I am pointing to.
(This folded paper is rotated about 45 degrees counterclockwise from how it’s shown at the end of the fold illustration. The long top pointed “tail” --diagonally to the left of the D of DESIGN–is under my knuckle.)
I looked for online instructions or a video, but have not found any.