It has been pointed out in an EOSC task force discussion that it is useful to be able to point to fragments of code in a diff, not just in a file.
Here is an example of what can be done in GitHub today:
[[ https://github.com/wikimedia/mediawiki-services-texvcjs/pull/38/files#diff-84bc28ec886369e8d279d3c006b1134dR761-R765 | https://github.com/wikimedia/mediawiki-services-texvcjs/pull/38/files#diff-84bc28ec886369e8d279d3c006b1134dR761-R765 ]]
It would be nice to provide a similar functionality in Software Heritage.