The Sites files have been redesigned for the 2020 release. There are 3 files: Sites, LP, Platforms.
Nevertheless some data is still of pitiful quality for the modern era. I was pretty proud of it in the days when the best one could do is measure off the Times Atlas of the World with a ruler, but in these days of Google Earth and kmz files, the reader should expect better. I have made improvements to the locations here and there and a systematic improvement is underway for the next edition.
The new Sites file, which shares some design features with the Organizations file, contains several categories of site:
The LP file contains specific launch pad or launch point locations for each site. The 'Launch Point' (LP) is a specific (and ideally precise) location from which a launch may occur An example of an LP is a fixed launch pad, e.g. Space Launch Complex 17A at Cape Canaveral. Another example is the geographical coordinates of a launch carried out from a ship or an airplane. Every LP is associated with an LS, LC or LZ.
The Platforms file lists ships, submarines and planes used for rocket launches.
Each of these LS and LP may change its name over time, and each one is given a code for each temporal phase, one of which is picked as the 'ucode' or unique code for the site or LP. The file contains the code and ucode for each LS and LP: The code for an LP consists of the LS code followed by a pad-specific part which changes indepdenently. For example, pad 36A at Cape Canaveral has the pad code LC36A and its LS is Cape Canaveral with ucode CC; the complete ucode for the LP is CC LC36A. The code for CC changes over time, and so (at different times) does the code for LC36A: CCAS LC36A and CC SLC36A both refer to this same pad. But there is also an LC36 at White Sands, WS LC36, so the pad-specific part must always be paired with the site.
The Sites file contains:
The Platforms file contains the following platform times: SHIP, SUB, AIR, and PLAT. PLAT refers to land-mobile launch platforms; the LC39 Mobile Launch Platforms are the only ones included right now but one can imagine adding mobile missile trailers. The other three are obvious.