Programs using HTTP typically report a user agent to avoid being blocked. User agent metadata help the server know user client statistics.
CMake’s HTTP user agent is like
as seen with CMake script.
Some servers may block CMake download traffic such as file(DOWNLOAD …). A web browser from the same computer may work–this is a symptom of server user agent blocking. This script demonstrates setting a custom HTTP user agent to get around servers that block non-allow-listed user agents.