The .ica is a computer file type, just like a .exe or .dmg or other similar file type; however, .ica file is a component of the Citrix Receiver sends input from your computer (i.e., keyboard and mouse inputs) to a remote system such as Blackbaud Hosting Services, and receives back the output such as video and sound. This is a necessary, key component of the Citrix Receiver's functionality. 

Certain browsers such as Chrome, or non-configured browsers will exude this behavior more than the fully configured, supported browsers Firefox and Internet Explorer.