Howard Chalkley, Senior Programme at Frontier described how 2.2 will store a list of all stars a player has visited, historical data not included. As Howard explained
“Beta 2.2 introduced a new GalaxyMap filter, that indicates which stars you have visited: this is based on a cache file stored locally, but does not include historical data. The file is stored in the Local Appdata path, typically:
“I have been asked for information on the format of this file – but the file stores internal star system ID numbers which are not particularly suitable for access by third-party tools. We have instead added a mechanism to allow data to be imported into this cache.
“If you write a file named ImportStars.txt into the same folder, with one star system name per line, then start the game, it will lookup the names and merge them into the cache. (If you have many thousands of star names in the file, it may take a few minutes to process)
“Once it is finished, it will rename the file so it doesn’t re-import them next time. It will report the total number of stars imported, the number of duplicates, and the number that failed lookup, via the message input window. This feature should be available in the next Beta release.”