PPI::XS provides XS-based acceleration of the core PPI packages. It selectively replaces a (small but
growing) number of methods throughout PPI with identical but much faster C versions.
Once installed, it will be auto-detected and loaded in by PPI completely transparently.
Because the C implementations are linked to the perl versions of the same function, it is preferable to
upgrade PPI::XS any time you do a major upgrade of PPI itself.
If the two fall out of sync, the integration between the two is designed to degrade gracefully. PPI::XS
is capable of determining which functions are no longer equal, and will simple leave the perl version
alone, deleting the C version to free up the memory.
If the versions of the two get so far apart that they become completely incompatible, PPI::XS will simply
silently not load at all.
Beyond that, there isn't that much more you really need to know. :)