I downloaded all the transcripts and annotation with biotypes from a human dataset through the Biomart R package, the listed transcript biotypes including: protein coding, processed transcript, retained intron, pseudogene, processed pseudogene, etc. When I looked at the ensembl website for transcript biotypes (https://useast.ensembl.org/info/genome/genebuild/biotypes.html), I found retained intron was a subcategory of processed transcript, similar as processed pseudogene was a subcategory of pseudogene. So it looks the biotypes listed in the biomart package were not categorized same as the ensmbl database. Does anyone have any idea how the biotypes in Biomart R package was assigned for each transcript? Is there any reference to look for details/interpretation of the biotypes in Biomart?