A file with ica extension is a configuration file that is created based on Independent Computing Architecture. It is used by Citrix application servers and contains configuration information about the connection between different servers. ICA files may contain link to a hosted application or in some cases to a desktop server for remote connection. These are text files that can be created, edited and viewed using any text editor such as Microsoft Notepad, Notepad++, or Apple TextEdit.
ICA File Format - More Information
ICA files are stored to disc in plain text format and are easily readable by humans. ICA files specify the parameters that the remote desktop client applications, such as Citrix Receiver, uses to connect to applications hosted on remote virtual desktops.
ICA files should conform to certain initialization and formats in order for successful connectivity. These are mentioned in Citrix ICA settings reference and includes fields such as :