The app logo.
Change game properties, change inventory, enchant, set TP areas, and spawn mobs.
MCPE Master is a launcher available for the Android version of Minecraft: Pocket Edition. It allows the user to choose different maps, mods, seeds, and texture packs. It is available for devices running Android 4.0.3 and up.
On the homepage, there will be a list of maps published for people to try out. When you press the download button, the map will be added to your maplist. You can also import maps downloaded from other sources in the "Import" tab.
On the homepage, there will also be a list of Skins to download and try. Trying to use your own skin in the game itself does not seem to work, and thus you will need to Import skins too.
The homepage also contains a list of seeds which people have found. Most seeds on the list are Villages, Desert Temples, and rarely extreme hills. There is no ability to import seeds as you can input it in the game itself.
The homepage has a list of textures, most of them either simplified, turned to a more elegant style, or shaders. Like most things, you can Import textures downloaded from other sources.
ModPE is an experimental feature. Mods are things which change the game, and are usually found in .apk files. However, you may also find .js mods, although these are usually not capable of adding much. APK files are more efficient, as they are capable of more, but the downside is that they usually required extra apps installed. And, after recent updates, you can import ModPE.
Warning: Enabling many ModPE's at once may cause lag, or in extreme cases, the game might crash on start.
The floating window is something which lets you edit things in-game. You can change the Time and Weather, change Gamemodes, add items or remove items to/from the inventory, spawn and delete Mobs, turn on flight, invincibility, constant sprint, or no-clip, enchant items wherever you are, and set places to teleport.
The floating window will disappear if you join a server to prevent abuse.