This template is identical to Template:Flag, except that the flag links to its image description page, for pages where the flag is for information rather than just decoration, or for non-public domain images for which attribution is required.
The c in the name refers to "clickable".
{{flagc|USA}}
→ USACompare:
{{flag|USA}}
→ USA - image is not clickable{{flag icon|USA}}
→ - image links to the country concerned