To be unseen. I couldn't find that picture because it had been lying doggo behind some boxes.
Fig. to remain unrecognized (for a long time). This problem has lain doggo since 1967. If you don't find the typos now, they will lie doggo until the next edition.
lie doggoremain motionless or quiet. British
Lie doggo is of uncertain origin, but probably arose from a dog's habit of lying motionless or apparently asleep but nonetheless alert.
lie ˈdoggo(old-fashioned, informal) be very still or hide somewhere so that you will not be found: I lay doggo in the yard while the police searched the house for me.
lie doggo(ˈlɑɪ ˈdɔgo)
in. to remain unrecognized (for a long time). (see also doggo. Old, but Standard English.) If you don’t find the typos now, they will lie doggo until the next edition.