This card's name is a Latinized version of the Welsh name, Caledfwlch. After the legend of King Arthur was introduced into French literature, "Caliburn" was translated to "Excalibur".
Interestingly enough, this card's first effect appears to be at least partly based on certain depictions of Excalibur's scabbard, which was said to have the ability to shield life, making it a near necessity on the battlefield.
This is the first and so far only "Noble Arms" Equip Spell that doesn't prevent the player from controlling more than one.
It also lacks the effect which lets it re-equip itself to a "Noble Knight" when it's destroyed, a trait shared by all the other "Noble Arms".
The blue light in the blade of "Excaliburn" refers to the light in the armor of "Artorigus, King of the Noble Knights", while the red light refers to the light in the armor of "Ignoble Knight of High Laundsallyn". This is specially notable due to the artwork of "High Laundsallyn", which shows him wielding this sword, and both sides of the blade form "Excaliburn" have red lights like those of his armor. Similarly, when "Sacred Noble Knight of King Artorigus" wields "Excaliburn", both lights are blue.