As far as I understand, macro-showhide is not part of the XWiki open source project, but maintained by XWiki SAS.
The project lead is Ludovic Dubost according to the readme.
As an XWiki SAS employee, I’ll ping internally so that somebody can look at your request.
Just some clarifications below (to make sure there’s no misunderstanding).
To be precise, it is part of the XWiki open source project. Any contrib project is part of it. I think you meant that it’s not maintained by the XWiki core devs who are working on the XWiki Standard / XWiki product.
Also there’s no concept of company maintaining anything in the XWiki oss project. There are only individuals. They can work for any company they want. You can check the lead and you’ll find it’s an individual, not a company.