Merci à vous !
C'est bien du HTML/CSS/JavaScript, et les autres langages sont à coder à la main.
J'ai eu leur réponse :
"Using Muse, you can create a site, which uses HTML/CSS/Javascript coding. All the languages that you have mentioned, can work on the site, but you need to add them manually. Means, once your site is ready, you can export your site as html and then you can add any scripting language like PHP, Python, depending on your requirement, so it will be great if you can decide which language you will use in future and purchase the hosting accordingly."
Merci encore à vous et bonne fin de journée !
Solenn