I wonder about icon of files in Project windows. Especially, what's different red colored three bars in the left and non bars of icon ?
Thanks.
Which is why it's important to state the version(s) of the tool(s) you're using in your posts!
Especially when they are old versions!
"however there is also a documentation that comes with the product (and this contains a similar page that explains the old icons)"
It is still available (though hidden?) online:
http://www.keil.com/support/man/docs/uv3/uv3_ca_filegrp_att.htm