The guide hasn't been updated since 2015. There was an informational letter in 2016 that said to use the 2015 guide for 2016 CRA data.https://www.ffiec.gov/cra/pdf/2016_CRA_Guide.pdf
The CRA file specs for 2019 mentions code 04 home equity. https://www.ffiec.gov/cra/pdf/2019Specs.pdf
If you are a HMDA reporter, you would be reporting all of your closed end credit home equity loans secured by a dwelling and your HELOCs if you exceed 500 on your HMDA LAR. Could code 04 perhaps still be available for an institution that didn't have to put their HELOCs on the HMDA LAR and chose to collect some data for those loans under CRA?