diff --git a/Static-filter-syntax.md b/Static-filter-syntax.md
index b84ce52..5962fa1 100644
--- a/Static-filter-syntax.md
+++ b/Static-filter-syntax.md
@@ -145,6 +145,8 @@ For example, [Adguard English filter](https://adguard.com/en/filters.html#englis
 
 uBO 1.14.23b3+ only.
 
+**READ VERY CAREFULLY:** HTML filtering acts on the **response data** (before browser parsing). Do not use the browser inspector from developer tools to create HTML filters. You **must** use `view-source:[URL of page]` instead to look at the **response data** and find out relevant HTML filter.
+
 The purpose of HTML filters is to remove elements from a document _before_ it is parsed by the browser.
 
 The syntax is similar to that of cosmetic filters, except that you must prefix your selector (CSS or procedural) with the character `^`: