API reference / Common / Engine types / TextBookmarkStart
Interface: TextBookmarkStart
A bookmark's opening mark (w:bookmarkStart, CT_Bookmark) — one unit, carrying the name.
A token pair rather than a container: w:bookmarkStart and w:bookmarkEnd are empty elements the file places anywhere in the content — across paragraphs, overlapping another bookmark — which is ECMA-376's "cross-structure" annotation (§17.13.2). So the model keeps the two marks as the file spells them, each a unit of the offset space, and the content between them is ordinary content of the parent's.
The marks are metadata: they paint nothing, the caret steps over them, and a delete across one leaves it in place, so a bookmark whose text is all removed collapses to a point rather than vanishing — Word's behaviour.
No character properties: a field's mark is a w:fldChar inside a w:r with an rPr, but a bookmark's mark is not a run.