Content Security Policy is best used as defense-in-depth, to reduce the harm caused by content injection attacks.
Meta Keywords are a specific type of meta tag that appear in the HTML code of a Web page and help tell search engines what the topic of the page is.
The http-equiv attribute provides an HTTP header for the information/value of the content attribute. The http-equiv attribute can be used to simulate an HTTP response header.
Windows-1251 (a.k.a. code page CP1251) is a popular 8-bit character encoding, designed to cover languages that use the Cyrillic script such as Russian, Bulgarian, Serbian Cyrillic and other languages.