What is "technosignature"

Technosignature or technomarker is any evidence of the operation of advanced technology by an extraterrestrial civilization, with the exception of the radio messages which are traditionally searched for in the search for extraterrestrial intelligence (SETI). First covered in Paul Davies's 2010 book The Eerie Silence and later developed by Iván Almár, technosignatures are analogous to the biosignatures that signal the presence of life, whether or not intelligent. Various types of technosignatures, such as radiation leakage from megascale astroengineering installations such as Dyson spheres, the light from an extraterrestrial ecumenopolis, or Shkadov thrusters with the power to alter the orbits of stars around the Galactic Center, may be detectable with hypertelescopes.