The DRF documentation is not detailed in this question (or I skipped the part where it is), but it mentions the rest_framework.schemas.SchemaGeneratorclass and it seems that this class really does all the introspective things. Fortunately, the source code is well structured and easy to read.
get_path_fields ( , : get_schema → get_links → get_link), , help_text.
, :
class MyResource(models.Model):
slug = models.CharField(unique=True, help_text=_("unique alphanumeric identifier"))
...