I forget exactly what's in this specific changeset, but the tracks and fences are from the Bing imagery in iD, sinkholes and names (and confirmation that all the above exists in these locations) are from local knowledge. Sinkholes and names are also available in the book The Caves of Fermanagh and Cavan, Ed2 (Fogg, Burns et al 1997) but I didn't use this reference as I've been to these locations and know them myself.