The wl_data_source object is the source side of a wl_data_offer. It is created by the source client in a data transfer and provides a way to describe the offered data and a way to respond to requests to transfer the data.
A.9.1. Requests provided by wl_data_source
A.9.1.1. wl_data_source::offer - add an offered mime type
This request adds a mime-type to the set of mime-types advertised to targets. Can be called several times to offer multiple types.
wl_data_source::offer arguments
type
Type: string
A.9.1.2. wl_data_source::destroy - destroy the data source