"ListItem" is hardcoded.

[hyuckkim]

BlockNote/packages/core/src/blocks/ListItemBlockContent/ListItemKeyboardShortcuts.ts

Line 13 in 6ce6e57

if (!contentType.name.endsWith("ListItem") || !selectionEmpty) {

I cannot how it works, but It works in custom block also.
I changed my custom block's type to JohnDoeListItem and use their feature.

I think it need to allow modification to boolean values in blockspec.

[matthewlipski]

Good point, didn't consider custom list item blocks which maybe shouldn't have the same behaviour as the default ones, will fix to only use the shortcut for BulletListItem and NumberedListItem.