Currently, the multisig descriptor constructions are limited to 16 keys only possibly because of template parsing reasons. Under p2sh context, such scripts would be invalid anyway because of 520-byte rule, but we can support up to 20 keys for CHECKMULTISIG in witness script context. 


{
    SCRIPT_VERIFY_NONE      = 0,
    
    SCRIPT_VERIFY_P2SH      = (1U << 0),
    
    
    
    SCRIPT_VERIFY_STRICTENC = (1U << 1),
    
    SCRIPT_VERIFY_DERSIG    = (1U << 2),
    
    
    SCRIPT_VERIFY_LOW_S     = (1U << 3),
    
    SCRIPT_VERIFY_NULLDUMMY = (1U << 4),
    
    SCRIPT_VERIFY_SIGPUSHONLY = (1U << 5),
    
    
    
    
    SCRIPT_VERIFY_MINIMALDATA = (1U << 6),