What is the scale unit used in the Gene Skyline databrowser, Is the data normalized?

The expression values shown in the Gene Skyline are normalized by DESeq2.

Here's a description of the common normalization methods in RNAseq analysis : https://hbctraining.github.io/DGE_workshop/lessons/02_DGE_count_normalization.html

As such, they do not have a precise scale ( like " transcription per  Million, TPM), although in practice they are not far from TPM.