The correct patched /var/lib/snmp/mibs/ietf/SNMPv2-PDU for Debian Linux and derived distributions (Ubuntu, MX Linux, etc.) :== https://supratim-sanyal.blogspot.com/2022/01/cisco-switch-decnet-routing-snmp-mib.html

SNMPv2-PDU

SNMPv2-PDU DEFINITIONS ::= BEGIN

ObjectName ::= OBJECT IDENTIFIER

ObjectSyntax ::= CHOICE {
      simple           SimpleSyntax,
      application-wide ApplicationSyntax }

SimpleSyntax ::= CHOICE {
      integer-value   INTEGER (-2147483648..2147483647),
      string-value    OCTET STRING (SIZE (0..65535)),
      objectID-value  OBJECT IDENTIFIER }

ApplicationSyntax ::= CHOICE {
      ipAddress-value        IpAddress,
      counter-value          Counter32,
      timeticks-value        TimeTicks,
      arbitrary-value        Opaque,
      big-counter-value      Counter64,
      unsigned-integer-value Unsigned32 }

IpAddress ::= [APPLICATION 0] IMPLICIT OCTET STRING (SIZE (4))

Counter32 ::= [APPLICATION 1] IMPLICIT INTEGER (0..4294967295)

Unsigned32 ::= [APPLICATION 2] IMPLICIT INTEGER (0..4294967295)

Gauge32 ::= Unsigned32

TimeTicks ::= [APPLICATION 3] IMPLICIT INTEGER (0..4294967295)

Opaque ::= [APPLICATION 4] IMPLICIT OCTET STRING

Counter64 ::= [APPLICATION 6]
              IMPLICIT INTEGER (0..18446744073709551615)

-- protocol data units

PDUs ::= CHOICE {
     get-request      GetRequest-PDU,
     get-next-request GetNextRequest-PDU,
     get-bulk-request GetBulkRequest-PDU,
     response         Response-PDU,
     set-request      SetRequest-PDU,
     inform-request   InformRequest-PDU,
     snmpV2-trap      SNMPv2-Trap-PDU,
     report           Report-PDU }

-- PDUs

GetRequest-PDU ::= [0] IMPLICIT PDU

GetNextRequest-PDU ::= [1] IMPLICIT PDU

Response-PDU ::= [2] IMPLICIT PDU

SetRequest-PDU ::= [3] IMPLICIT PDU

-- [4] is obsolete

GetBulkRequest-PDU ::= [5] IMPLICIT BulkPDU

InformRequest-PDU ::= [6] IMPLICIT PDU

SNMPv2-Trap-PDU ::= [7] IMPLICIT PDU

--   Usage and precise semantics of Report-PDU are not defined
--   in this document.  Any SNMP administrative framework making
--   use of this PDU must define its usage and semantics.

Report-PDU ::= [8] IMPLICIT PDU

-- max-bindings INTEGER ::= 2147483647

PDU ::= SEQUENCE {
        request-id INTEGER (-214783648..214783647),
        error-status                -- sometimes ignored
            INTEGER {
                noError(0),
                tooBig(1),
                noSuchName(2),      -- for proxy compatibility
                badValue(3),        -- for proxy compatibility
                readOnly(4),        -- for proxy compatibility
                genErr(5),
                noAccess(6),
                wrongType(7),
                wrongLength(8),
                wrongEncoding(9),
                wrongValue(10),
                noCreation(11),
                inconsistentValue(12),
                resourceUnavailable(13),
                commitFailed(14),
                undoFailed(15),
                authorizationError(16),
                notWritable(17),
                inconsistentName(18)
            },
        error-index                 -- sometimes ignored
            INTEGER (0..2147483647),
        variable-bindings           -- values are sometimes ignored
            VarBindList
    }

BulkPDU ::=                         -- must be identical in
    SEQUENCE {                      -- structure to PDU
        request-id      INTEGER (-214783648..214783647),
        non-repeaters   INTEGER (0..2147483647),
        max-repetitions INTEGER (0..2147483647),
        variable-bindings           -- values are ignored
            -- VarBindList
	    SEQUENCE (SIZE (0..2147483647)) OF VarBind
    }

-- variable binding

VarBind ::= SEQUENCE {
        name ObjectName,
        CHOICE {
            value          ObjectSyntax,
            unSpecified    NULL,    -- in retrieval requests

                                    -- exceptions in responses
            noSuchObject   [0] IMPLICIT NULL,
            noSuchInstance [1] IMPLICIT NULL,
            endOfMibView   [2] IMPLICIT NULL
        }
    }

-- variable-binding list

-- VarBindList ::= SEQUENCE (SIZE (0..2147483647)) OF VarBind

END