Filters can be used without fully qualifying their path by putting them in a filters subdirectory of Pandoc’s --data-dir (e.g. $HOME/.pandoc).
Distribution packages
Debugging
Standalone executables that filter a JSON representation of the Pandoc AST through standard in/out. Can be “plumbed” automatically with Pandoc’s --filter option (which additionally provides command line arguments and environment variables, see the docs).
pandocfilters, Python library
panflute, Python library
pandoc-filter-diagram, Binary and Rust library
Pandoc >=2.0 embeds a Lua (5.4) interpreter and associated library. Filters are passed with --lua-filter.
Ad-hoc - https://stackoverflow.com/questions/60854853/integrate-graphviz-into-pandoc/60915198#60915198