there are 30 minutes remaining until the end of the class

[GoldfishLord]

Accoding to https://www.ldoceonline.com/dictionary/remaining, "remaining" as an adjective is used only before a noun.
But we can say this: there are 30 minutes remaining until the end of the class.
Would someone please explain the red part?

 

[jutfrank]

Explain what exactly? I suppose the dictionary is saying that when it comes after, as in your example, it's a verb.