One of the few times where "Logres" isn't the name of Arthur's Kingdom.
The concept of Logres in Arthurian Literature is actually a bit more fluid than I had previously thought. Being derived from the Welsh name Lloegyr, Logres generally refers to the territory that is now known today as "England", the southern and eastern areas of Great Britain that was occupied by the Angles and Saxons in 6th Century.
With the Romance tradition, Logres becomes the name of Arthur's kingdom, a realm of knights and adventures. Sometimes Logres refers to a city in Arthur's kingdom and sometimes it's even conflated with the city of London, like in Vulgate Merlin:
So the maiden in Tyolet is probably meant to be a Saxon princess looking for a potential husband in Camelot, which is presumably located in Cambria/Wales.
Otherwise, this just becomes a silly scene of a random maiden claiming to be daughter of the King of Logres... to Arthur, the king of Logres.
Although given that Tyolet's story strangely resembles Percival's story, the writer of this Lai might have either gotten his info mixed up or just simply constructed this story for artistic exercise. For further context, this Lai is estimated to be composed the late 12th/early 13th century, which is right around the cusp of the Vulgate cycle's era. The Lai itself is found in a manuscript that is dated to the late 13th/early 14th C.
On a humorous level, I do kinda want to amuse myself that this is Archfedd trying to trick her dad into giving her a husband from one of his knights.