Effectively, every C library needs to do that, usually reserving some prefix.
It’s just a way to state “if you’re using this API/library, be prepared that future versions may introduce additional symbols matching these patterns, and/or that the current version may define undocumented symbols matching these patterns”. You then have the choice to take care to not define symbols conflicting with that.
The alternative would be for libraries to just add arbitrary new symbols, with no way for client code to proactively prevent conflicts.
It’s just a way to state “if you’re using this API/library, be prepared that future versions may introduce additional symbols matching these patterns, and/or that the current version may define undocumented symbols matching these patterns”. You then have the choice to take care to not define symbols conflicting with that.
The alternative would be for libraries to just add arbitrary new symbols, with no way for client code to proactively prevent conflicts.