PCI-Express Internal Physical Disk • GUID Partition Map

PCIe replaces SATA as the connection method, (which had replaced SCSI) and a Solid State Drive (SSD) is used in modern Macs because it is much faster than a Rotating Magnetic Drive, and has far lower access times, but some more complex writing procedures internally.

GUID partition Mac replaces MBR partitioning, (MBR was limited to 2.2TB maximum Volume size) but that happened a Long time ago, about MacOS 10.4 circa 2005.

the complete answers would produce a book-length reply.

Could you be a bit more specific about what and why you want to know about these items?

That is the internal drive in your Mac.