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This page tries to explain as much of the theming jargon as possible.

Word List


An archive. In the Switch's menu files it contains the layout files, animations and textures. More Info


A kind of title/app/game. Qlaunch, playerSelect, photoViewer are all applets. More Info

Applet Button

An 'applet button' is a bit different from 'applet'. The album, settings, controller, etc. buttons on the Home Menu are all applet buttons.


Unfortunately SZS files from the Switch's firmware files contain copyrighted data and can't be shared online. In order to still share custom themes, the nxtheme format was developed. An nxtheme file contains theme details (name, author), images and the layout.


The exelixbg is the name of the panel that is created when the NXThemes Installer or Switch Theme Injector apply a background image.

Diffing, Diffed JSON, Layout JSON

A layout is created by comparing a modified SZS file with the original unmodified one. The changes that are detected are saved in a layout json file, which then only contains differential data. This way, sharing nxthemes is completely legal.


Another term for elements in bflyt files. For example P_Pict, N_Button.

usd section

usd (officially called 'extended user information') is a part of the bflyt file that holds extra data and defines, for example, shadows, radius, etc. Panes are often followed by usd sections. More Info


Short for system update