Why are these meta tags needed?

Question

Search Engine Optimization

Hello,
I found in my code:

<meta HTTP-EQUIV="Pragma" CONTENT="no-cache">
<meta HTTP-EQUIV="Cache-Control" CONTENT="no-cache, must-revalidate">
<meta http-equiv="Content-Language" content="ru">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1251">
<meta content="index, follow, all" name="robots">
<meta content="5 days" name="revisit-after">

what is needed from this, and what can be removed / added.
thanks for the advice.

Answer 1

those that are http-equiv - see headers http ://ru.wikipedia.org/wiki/%D0%A1%D0%BF%D0%B8%D...
penultimate www.metatags.info/meta_name_robots
last see here www.webotdel.ru/notes/metatags