Here is what I find interesting:
Note the heavy brazing attaching the seat stays: The Holland

The brazing is much thinner on the Holland, you can see the definition of the point against the lug.
Mystery Frame

Here /\ it's like it the stay joins the lug in a sea of braze, the tip also has 4 facets and not as refined.
Then, the underside of the down tube has the lug uncut, leaving a large tab. Is this for support? A large rider?

Also the head tube is blue, is the frame original or a repaint? If it's repainted, are the box lines and chrome part of the repaint? Maybe a pre-war frame?