register_block_style_handle()

register_block_style_handle() — Finds a style handle for the block metadata field. Detects when a path to a file was provided and registers the style under an automatically generated handle name. It returns the unprocessed style handle otherwise, except for the first style of a core block, which is instead registered from the block’s own stylesheet when separate core block assets are loaded. Core blocks accept only handles, not paths.

Inputs: $metadata (array): Block metadata. $field_name (string): Field name to pick from metadata. $index (int): Optional. Index of the style to register when multiple items passed. Default 0.

Returns string|false: Style handle provided directly or created through style’s registration, or false on failure.