As requested by the community, the property P4839 (Wolfram Language entity code) that is currently a string, should be turned into an external identifier.
The reason why it was not done in the first place, URLs of the website not working, should not be considered as a blocker for an external identifier.
Just left a note on the property talk page (weakly) opposing this change. There I explain, why (to keep the discussion in one place).
I changed my mind as mentioned on the talk page: Support for changing this property to external ID.
Is everyone fine to change the datatype of P7007 (Wolfram Language unit code) to external ID as well? (discussion)
@Lea_Lacroix_WMDE does this have enough support to go ahead?
I only see 1 support in the linked discussion?
It might make sense for some admin or wikidata user to close the discussion with a decision?
Mentioned in SAL (#wikimedia-operations) [2019-11-12T19:45:41Z] <Amir1> ladsgroup@mwmaint1002:~$ mwscript extensions/Wikibase/repo/maintenance/changePropertyDataType.php --wiki=wikidatawiki --property-id P4839 --new-data-type external-id (T234221)
Mentioned in SAL (#wikimedia-operations) [2019-11-12T19:46:09Z] <Amir1> ladsgroup@mwmaint1002:~$ mwscript extensions/Wikibase/repo/maintenance/changePropertyDataType.php --wiki=wikidatawiki --property-id P7007 --new-data-type external-id (T234221)