Is the AlphaFold2 PDB structures available for download predicted using the UniProt canonical sequence?

Hi! I've download the compressed prediction files for model organism proteomes for Homo sapiens through this link https://ftp.ebi.ac.uk/pub/databases/alphafold/latest/UP000005640_9606_HUMAN_v4.tar, I wonder, is the AlphaFold2 PDB structures available for download predicted using the UniProt canonical sequences? Or most part of the structures were predicted using the UniProt canonical sequences, there were still some UniProt isoform sequences? Could the relevant information be found in the article "Highly accurate protein structure prediction with AlphaFold" or on the website (https://alphafold.ebi.ac.uk/)?