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My best guess here that these are exit holes from galleries made by a Flatheaded borers, or larvae of some members of Buprestidae family. The adults are known as Jewel beetles or Wood-boring beetles, while the larvae are named as mentioned.
Found on a discarded felled log and bark fallen off it on a forest floor of mixed (oak, beech, fir and spruce) lowland forest, hills in Geneva lake valley, at the feet of Jura mountain range.