Unexplained term in 8.5 (Shadow DOM slots, composition)

[vsemozhetbyt]

Slot API section uses the term "slottable" in the code example. This term happens only once on this page and may need an explanation (or a reference?). Otherwise, this comment may be a bit confusing (for example, 'slottable' may seem like a ref to a missing variable in the code):

// slottable is added/removed/replaced