I have taken a stab at splitting the `backward` file into sections. This is based on repeated observations made by multiple people that the file represents different kinds of Link. https://github.com/eggert/tz/pull/33 The sections I'm suggesting are: CROSS-ISO - These link across an ISO-3166 boundary EXCESS - These were added despite the locations having the same timekeeping since 1970 RENAMED - These are simple aliases/renames OBSOLETE - These are the most obsolete form of IDs FIXED - These are alternate names for fixed offsets I don't expect this PR to be merged as is - There will probably need to be some consideration as to the correct split, and as to whether each ID is in the correct section. The approach I've used is commented sections with stable section names. Alternate approaches to this problem are possible. For example, a new file could be created for each section. That seems to be more disruptive than the proposed approach. Note that in order for this change to be useful, the section names need to be considered part of the source file API, and maintained over time. thanks Stephen