Definition of "beflagged"

It amuses me to think by day, when broad awake in my sad English prison, and among my crazy peers, how this nightly umbrageous French solitude of mine, so many miles and years away, is now but a common, bare, wide grassy plain, overlooked by a gaudy, beflagged grand-stand.

1891, George du Maurier, “Part Sixth”, in Peter Ibbetson […], New York, N.Y.: Harper and Brothers, […], page 410

All other folks slumbered and took their rest: Vaekehu, the native Queen, in her trim house under the rustling palms; the Tahitian missionary, in his beflagged official residence; […]

1892, Robert Louis Stevenson, Lloyd Osbourne, “Prologue. In the Marquesas.”, in The Wrecker, London, Paris: Cassell & Company, […], page 1

There was little ceremonial to mark the opening of the completed railway beyond the fact that a decorated train left Paddington at 8 a.m. on the morning of June 30 a hundred years ago and, passing the beflagged ends of Box tunnel, arrived at Bristol at noon.

1941 November, “Notes and News: G.W.R. Main-Line Centenary”, in Railway Magazine, page 521