They are small text files stored by the browser (e. g. Google Chrome, Safari, Edge...) in the computer, tablet or phone from which you visit sites, and that are used to remember data across different visits.
The syneidis.com website makes use of two third party cookies:
Two from Google Analytics to track users' behaviour anonymously (i. e. these cookies do not let us trace you to an identity). Specific names for these cookies are _ga and _gid.
Cloudflare, the content delivery network provider we use for better performance of the site, uses its own anonymous cookie named __cfduid for attack prevention, load balancing, and other network engineering for optimizations.