Where are skins stored?

[clatix]

I'm using MusicBee version 3.4.7764 and Windows10 20H2 build 19042.985
I'm quite confused on using skins.

MySkin.xml is stored in two directories.
The first is "MBDirectory" whre the MB software is located and this is used  when I make a backup File/Library/Backup Library.
The second is in Users/My/AppData/Roaming/MusicBee/Skins and here I can find modifications on MySkin.xml
How could happen the two MySkin.xml are not identical?

I will appreciate any clarification.
Thank you very much.

[Steven]

if you are using the Portable MB verison, only the Skins sub-folder where MB is installed is used.
if you are using the Desktop or Store MB verison, the Skins sub-folder where MB is installed is used as first priority. Because that folder is not writable, MB also checks Users/My/AppData/Roaming/MusicBee/Skins.
If the same skin name is detected, MB should use the one with the latest modification date