Wikipedia claims that the Ꝇ / ꝇ is an old ligature for elle (LL / ll) in Spanish:
An old ligature for Ll is known as the "broken L", which takes the form of a lowercase l with the top half shifted to the left, connected to the lower half with a thin horizontal stroke. This ligature is encoded in Unicode at U+A746 (uppercase) and U+A747 (lowercase) and displayed (by the browsers that allow it) Ꝇ and ꝇ respectively.
but this claim is uncited and I can find no other references to its use in Spanish handwriting (nor as a printed character) anywhere online, except for a single (again, un-cited) short comment on one stack-exchange post:
Bueno, para el dígrafo ll existió la ele rota, una ligadura de dos eles: Ꝇ ꝇ, pero no estoy seguro si se usaron de manera significativa en textos castellanos.
Does anyone know anything more about its usage historically in Spanish (or have any examples of its use)?
The user Anárion is the originator of this information in the Wikipedia page, adding it as part of an edit at 09:25, 21 February, 2005 (archived version of page). It was added uncited (like many additions at the time), and seems to have remained as an unchecked legacy paragraph.