I'm trying to understand 是。。。的 constructions. The page on such constructions at Chinese Grammar Wiki explains one way to use 是。。。的:
This is the most simple way to use 是 with 的: you drop the noun and let 的 represent it. This usage requires context; otherwise the other person won't know what noun you are referring to. Having the 的 take the place of the noun is sort of like the way we say "one" or "it" in English. It's a basic substitution, but it's one that is very common and very helpful in everyday Chinese.
And gives these examples:
你 也 是 大学生 ？你 是 什么 专业 的 ？ Nǐ yě shì dàxuéshēng? Nǐ shì shénme zhuānyè de? Are you also a college student? What's your major?
我 是 中文 专业 的 。 Wǒ shì Zhōngwén zhuānyè de. My major is Chinese.
I don't understand this. 的 does not represent the noun - 什么 does. Is it better to say that 的 just follows at the end of the sentence, rather than that it actually represents the noun?
(Chinese Grammar Wiki article accessed here: https://resources.allsetlearning.com/chinese/grammar/The_%22shi..._de%22_patterns:_an_overview)