Comment by Someone

Maybe, but PDF can contain Flash Applets, too.

However, modern version of Acrobat Reader do not support that anymore. https://helpx.adobe.com/acrobat/kb/flash-format-support-in-p...:

“Flash Player end-of-life (EOL) impacts playback and authoring of rich media having Flash content (.flv and .swf) in PDFs:

• Playback of Flash media (.flv and .swf) content in existing PDFs will not be supported.”