Data from 2022 Stack Overflow Developer survey
The matrix is symmetrical in absolute numbers but not in relative numbers. This is because each language has a different total number of approvers. For example, consider the 168 people who approved of both COBOL and Go. There are 80547 people who approved of Go in general, so the people who also approved of COBOL is just 0.2% of all Go-approvers. However, only 5432 people ever approved of COBOL. Hence, 3.1% of all COBOL-approvers have approved of Go.
This is why, if Go is elected, COBOL-approvers are severely reweighted against - 3.1% of their voters have been represented through Go. This doesn't indicate that COBOL and Go are very similar or complements each other, but that many COBOL voters are also associated with Go. This is a one-direction relationship and does not indicate the relationship of Go voters with respect to COBOL.
How many people who approved of [row], also approved of [column]?
Each row sums up to 100%