Base of operations:
Matilda is Gyro Gearloose's girlfriend.
Comics: Walt Disney's Comics and Stories #310 (1966)
Country of origin:
Matilda is one of the rather obscure characters in the Disney universe. Her first appearance was in Walt Disney's Comics and Stories
#310 from 1966, as a love interest for Gyro Gearloose. Most likely she was not supposed to be used again, as Lockman only used her in that story. Over the years she has been used 13 times in stories, last record being from 1992, and the remaining stories have been produced in Brazil from 1973 onward.
There are no records of the character being transferred to other media, and considering how little the character has been used, it is unlikely she has been transferred to other media.