These commands are displayed only if a text layer is present.
In the Text to Selection drop-down list, the commands are identical to those of the Transparency sub-menu (in fact, the text is formed of areas of different transparency):
Text to Selection: 「Alpha to Selection」
Add to Selection: 「Add Alpha channel to Selection」
Subtract from Selection: 「Subtract from Selection」
Intersect with Selection: 「Intersect Alpha channel with Selection」