Replacements of some obsolete terms in `efo_otar_slim.owl` point to terms which aren't contained in it

[tskir]

Hi, while working with the replacements for obsolete terms we noticed that there are some obsolete terms in efo_otar_slim.owl where the replacement term is not contained in that same file itself.

For example: BTO_0000664 is in efo_otar_slim.owl. It's obsolete, and pointing (obo:IAO_0100001) to EFO_0002067 as its replacement.

However, while EFO_0002067 is contained in efo.owl, it's not present in efo_otar_slim.owl. This causes issues for libraries such as pronto, which are trying to parse and follow the "replaced by" links, and expect the replacement terms to be present in the same ontology.

For this particular concept, it seems sensible that its modern identifier isn't included in the OT slim, because it's a cell line and not a disease. However, it's the inclusion of the obsolete term which seems to be problematic here.

As such, we were wondering if it would be possible to revisit and delete such terms on your side?