That is MK's Flickr page. He is the person that provides the ERAS content and he posted pictures from ships he has added to his own version, but not yet released to me. However, he has mentioned to me that at some point he intended to give them to me for addition to the public version. Since you asked, I called him this morning and mentioned your inquiry.
He told me that he has about 10 ships he has added to his personal version, but is now working on an additional 20 more ships and for about 5 of those, he intends to simply replace some existing ERAS ships that he doesn't like. He thinks that he can finish the texture work for them by February 2025 and will give them to me for upload to Itch. He says that since you asked about them, he feels that provides him motivation to continue working on them and he promises to complete them and provide them to the public version.
That's all I know so far.