–Partner emails (registration received, approved, welcome to B2B, change request received/decided) are now sent in the SITE language instead of the administrator's personal language, and are translatable.
–Admin notices and the registration "required field" error are translatable; the invoice legal note has an English source with the Bulgarian text in the bg_BG catalogue.
–WordPress.org compliance pass: translator comments and integer casts — no change in behaviour.
–Update URI header so WordPress never replaces this self-hosted build with the free WordPress.org build.