We need also to recognize that there are two types of technology in the planet earth. Human and non-human technology. Is widely accepted that some species other than Homo sapiens developed technology. Many of this animals are in the family hominidae but a beehive for example could be accepted as bee technology. It has a well defined purpose, implies several examples of material design and manipulation. what bees evolved to keep warm in winter is not much different than ours wood cabins, pantries and bonfires. The acari that is riding a honeybee to move far than its range is not too different than us learning how to ride a horse for the same purpose. We adopted and replicated a lot of animal technology like paper, but not all. We still don't dominate the technology to make a clam shell from scratch for example.

Identifying extraterrestrial technology in the planet could be much more difficult because we need also to be able to separate it from non human technology. That technology could be much more subtle than the festival of ligths and steel that we see in the films. Until data most if not all of the "extraterrestrial" signs were found to have a perfectly normal terrestrial explanation.