If you are an ed tech practitioner then, the sense is less of a excavation, and more one of hurried gathering. Ed tech practitioners operate like mudlarks, gathering artefacts that have been exposed by the last technology tide (see below reservations on this). These artefacts can be seen as nuggets of good practice, research or concepts that have application across different technology. Things like how to support learners at a distance, how to effectively encourage online dialogue, ethics of application, etc.
Martin Weller wonders about another edtech metaphor, this time of digital mudlarking.