The meaning of って (No quotation, No "even if") [duplicate]

Question

I found a lot of questions about って here, but none helps me to understand the nuance of the following sentence:

ね、あの子の言う少佐って誰のこと？

It does not seem to be the quotation because の言う is already used before.

And "even if" also does not fit in this sentence.

Can you please tell me the meaning of って in this case?

For context: This is a sentence from Violet Evergarden. It is said at 22:38 in the second episode (https://9animetv.to/watch/violet-evergarden-59?ep=1452)

The women saying the sentence heard Violet speak about a certain Major and would like to know who that person is.

Answer 1

As suggested by Chocolate the answers to the two below questions answer my question as well.

In this case って is the topic marker.

The sentence could change to the following:

ね、あの子の言う少佐って誰のこと？ --> ね、あの子の言う少佐は誰のこと？

Difference between って and は as topic marker

Confused about って in this sentence