The BSD ‘disklabel’ mechanism is an old partitioning scheme from 1988. Avoid using it, nowadays.
To put it into historical context: disk partitioning had been the province of high‐end mainframe systems until less than a handful of years before the ‘disklabel’ was invented. The MBR‐style disc partitioning system that was being used in the PC world had only properly taken form less than a handful of years earlier, in 1984 with the release of PC-DOS 3.0.
At the time of their invention, ‘disklabels’ were the BSD world's response to the same pressures that were causing people to partition discs when running other operating systems. They had distinct BSD spins on the concept, including things like cylinder‐to‐cylinder slew factors for sector 0, drive rotational characteristics, and block fragments.
In the second quarter of the 21st century, though, BSD ‘disklabels’ are a scheme that was overtaken by better mechanisms almost 30 years earlier. They are now simply remnants of older ways of doing things that are easy to mis‐use and wipe out your GUID Partition Table or PC/AT firmware on‐disc Boot Manager.
They use 32‐bit fields, and sometimes 16‐bit ones, and because of that suffer the same 2 TiB disc and partition size limits of other 32-bit schemes. Whereas GUID Partitionining, introduced as part of EFI at the turn of the 21st century, uses 64-bit addressing and does not have these limits.
They are not even a single coherent system any more. NetBSD's, OpenBSD's, FreeBSD's and DragonFlyBSD's evolutions of the original scheme have all significantly diverged. They do not agree on partition type codes beyond IBM's JFS2. In particular, they disagree on what the partition type codes for ZFS and HAMMER2 partitions are.
They have not been binary compatible on‐disc since DragonFlyBSD invented its own 64‐bit ‘disklabel’ data structure. And since 2025, they are not even binary compatible on‐disc for the better‐known BSDs, as that year OpenBSD got rid of the ‘v0’ on‐disc data structures (with an optimistic note in the version control log that nobody had written old version disklabels to disc since 2007).