You get these by collecting map pieces. Small locations, with themed contents, plus a level 1 digspot, giving a chest. Each chest should have either a figure of enlightenment, or a blueprint, plus a bunch of other stuff.
Where to FIND
1 available in Kafaree, for 10 tulips or 10 roses, from Garden Puzzle, or 10 tulips from Thornville. Little man standing next to big oak tree, top corner of garden area.
1 Thornville library, found in a book, either rip it out or (intelligence stat?) or make a copy.
2 Smugglers cache, found in chests.
Can also be found in (Movement bonuses, on world map) message in a bottle (at sea) or lost letter (on land). About a 1 in 8 chance.
Underwater locations. Opposition Hideout, about half the others.
First location needs 2 map pieces, 2nd 3 map pieces, 3rd 4 map pieces.......etc. Most people will get 2 locations, 3 is possible, 4 is hard, have never had 5. You will get a random selection. Rumour has it, about 20 different ones available?
https://imgur.com/a/treasure-spots-wBOpYQ5 Sorry about the highlighted text, not sure why it happened or how to fix it.