Cannot open file from project mate, but another mate can. "File is rather binary than text so cannot be opened by the source editor"

File in TEAMS stands as ".RData" implying no name, but being RData? But when I download it, it gets saved as RData, implying name=RData but no (dot) ending, implying no specific file type? I try to open it through RStudio, and get the error "File is rather binary than text so cannot be opened by the source editor". I open through RStudio File -> open file.. then selecting my file and get this error. I tried to open through commands and get the same error. I can manage to load into enviroment to see variables. But i want to see the whole source code, which my other mate can see.
I tried renaming the file to .RData as a result, I get asked if I want to load it into my global environment. I cant access the source code. Also tried renaming like .rda .r .txt

Can you help me please?

Hi @kazzam,
Welcome to the RStudio Community Forum.

An .Rdata file is in binary format and contains all the data objects present in the Global Environment when the R session was terminated. It does not contain the R commands (code) that created or modified those objects. Check to see if the R code was saved in a separate R script file ending in .R or .r.
If none exists, the command history may have been saved in a file named .Rhistory. The contents of this file can be copied into the RStudio code editor and tidied-up, and saved for re-use.