How to change file types in Google Drive?

Question

I have 2 files in My Drive with ipynb extension. One is marked as Unknown file type and has a blue icon, and the other is marked as Colaboratory type.

How do I change both to be Colaboratory?

Answer 1

An identical question has been asked on StackOverflow - .ipynb file in Google Drive doesn't open with Colaboratory by default. The accepted answer by @JeffRush can be summarised as follows:

"If you want to get that icon you should save a copy from Colab"

His detailed answer includes an explanation of the steps to do this.