I actually found someone with a similar request. https://open.canada.ca/en/search/ati/reference/9e385830c1c16e89d0b9956b1d3226cd see this ATIP request. they requested in may 2022, and their question was about PR applications, so I don't think it'll include abbreviations used in citizenship applications but just wanted to show that we can probably request this information from IRCC using ATIP.