diff --git a/README.md b/README.md
index 5163e29..98ece62 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ Currently to do:
 This project is designed to match the upstream [specification](https://github.com/misskey-dev/media-proxy/blob/master/SPECIFICATION.md), however a few deviations are made:
 
 - We will not honor remote `Content-Disposition` headers but instead reply with the actual filename in the request URL.
-- Remote `Content-Type` headers will only be used as a hint rather than authoritative, and resniffing is unconditionally performed.
+- Remote `Content-Type` headers will only be used as a hint rather than authoritative, and resniffing is unconditionally performed using the `file` utility database using purely masked signature matching.
 - SVG rasterization is removed from the proxy in favor of sanitization and CSP enforcement.
 
 ## Demo