Quick way to extract all attribute names and write to a document?

Dear Community,

I want to depivot a wide table which has names like

Pages[0].Item.Version

Pages[0].Item.Language

Pages[0].Url.Path

Pages[0].VisitPageIndex

Pages[0].Duration

.

.

.

Pages[1].Item.Version

Pages[1].Item.Language

Pages[1].Url.Path

Pages[1].VisitPageIndex

Pages[1].Duration

I used a regex in 'select attribute' to filter the wanted attributes, then I de-pivot the table. But I feel it is more convenient if I can copy all the attribute names from a flat document...

Thanks in advance!