Have you come across a file claiming to be XKEYSCORE source code? Approach with extreme caution. It is likely malware, a honeypot, or a classified trap. When in doubt, contact a digital rights organization like the EFF or ACLU for guidance.
One famous line (paraphrased from a 2013 presentation):
// From ANT's "RAGEMASTER" implant int xks_send_to_processor(uint8_t *payload, size_t len, enum xks_tag type);
The existence of XKeyscore—a powerful surveillance system used by the National Security Agency (NSA)—first came to light in 2013 through documents leaked by Edward Snowden. Described as the NSA's widest-reaching system for developing intelligence from the internet, XKeyscore allows analysts to search through vast databases of emails, online chats, and browsing histories of millions of individuals. Since its disclosure, there has been significant interest in the underlying mechanics of this tool, specifically regarding the xkeyscore source code.