2.1.119 [W3C-HTML51] Section 8.2.4.39 Attribute value (single-quoted) state

V0307: NULL character U+0000 does not produce a parse error prior to changing the character to the replacement character U+FFFD

The specification states:

 ... Attribute value (single-quoted) state
  
     Consume the next input character:
         ...
         U+0000 NULL
  
             Parse error. Append a U+FFFD REPLACEMENT CHARACTER character to the current 
             attribute's value.

EdgeHTML Mode

NULL character U+0000 does not produce a parse error prior to changing the character to the replacement character U+FFFD.