I'm unsure how to view the *.gz files (e.g. fld and biases files) in the "aux_info" folder after running Salmon. After unzip the .gz files, they are still not in human readable format. Is another tool required to access these files? Any suggestions are appreciated.
See the Salmon docs: here. These are gzipped, but in a binary format which the docs describe. Based on a quick look at the descriptions, it appears you could get the contents of these files by reading the uncompressed contents and decoding them using binary constructs available in many scripting languages like Python, Perl, or R.