The Turkish Wiki has, translatedm, amongst other things "İshak Fakih Mosque is a late Germiyan work in Kütahya dated 1433 and was built by the famous Kütahya fiqh scholar İshak Fakih." and it mentions a drinking fountain was here, erected in 1420. In 2018 I found the mosque closed, a lot of restoration seemed to have taken place near it, the pictures show the mosque in its setting.