!!! Overview
[{$pagename}] are what [{$applicationname}] uses to define [LDAP Schema Element Extensions].


Various [DSA] support Extended Attribute Flags that may provide additional information about the [AttributeTypes] and [ObjectClasses]. 

[{$pagename}] are described as [Experimental] in [RFC 4512] \\
"''Implementors should note that future versions of this document may expand these definitions to include additional terms.  Terms whose identifier begins with "X-" are reserved for private experiments and are followed by <SP> and <qdstrings> tokens.''"

[LDAP] __does not define__ any standard schema extensions, but many [LDAP Server Implementations] accept any properly-formatted extension as a means of annotating the schema element. 
For [example], one of the most commonly-used extension types is [X-ORIGIN], which is typically used to indicate the source of the associated schema element, and the string [X-ORIGIN] RFC 4519 might be used to indicate that the associated schema element is defined in RFC 4519.

These Extended Attribute Flags are typically specific to each individual [LDAP Server Implementations] and are prefixed with a "X-".
Some popular [examples]:
* [X-ALLOWED-VALUE] - Specifies the set of values that attributes of that type will be allowed to have.
* [X-APPROX] - Specifies the name or OID of the approximate matching rule that should be used in conjunction with the specified [attribute Type].
* [X-MAX-INT-VALUE] - Specifies the maximum integer value that attributes of that type will be allowed to have.
* [X-MAX-VALUE-COUNT] - Specifies the maximum number of values that attributes of that type will be allowed to have.
* [X-MAX-VALUE-LENGTH] - Specifies the maximum number of [UTF-8] characters that values of attributes of that [attribute Type] will be allowed to have.
* [X-MIN-INT-VALUE] - Specifies the minimum integer value that attributes of that type will be allowed to have.
* [X-MIN-VALUE-COUNT] - Specifies the minimum number of values that attributes of that type will be allowed to have.
* [X-MIN-VALUE-LENGTH] - Specifies the minimum number of UTF-8 characters that values of attributes of that type will be allowed to have.
* [X-NDS_ACL_TEMPLATES]
* [X-NDS_BOTH_MANAGED]
* [X-NDS_CONTAINMENT]
* [X-NDS_ENCRYPTED_SYNC]
* [X-NDS_FILTERED_OPERATIONAL]
* [X-NDS_FILTERED_REQUIRED]
* [X-NDS_HIDDEN]
* [X-NDS_LOWER_BOUND]
* [X-NDS_NAME]
* [X-NDS_NAME_VALUE_ACCESS]
* [X-NDS_NAMING]
* [X-NDS_NEVER_SYNC]
* [X-NDS_NON_REMOVABLE]
* [X-NDS_NONREMOVABLE]
* [X-NDS_NOT_CONTAINER]
* [X-NDS_NOT_SCHED_SYNC_IMMEDIATE]
* [X-NDS_PUBLIC_READ]
* [X-NDS_READ_FILTERED]
* [X-NDS_SCHED_SYNC_NEVER]
* [X-NDS_SERVER_READ]
* [X-NDS_SYNTAX]
* [X-NDS_UPPER_BOUND]
* [X-NOT-HUMAN-READABLE]
* [X-ORIGIN] - is typically used to indicate the source of the associated schema element and is often the [LDAP] [RFC] where the Schema element is defined.
* [X-SCHEMA-FILE] - 
* [X-SYSTEMFLAGS]
* [X-SCHEMAFLAGSEx] 
* [X-SEARCH-FLAGS]


!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Schema Element Extensions|https://ldap.com/schema-element-extensions/|target='_blank'] - based on information obtained 2018-10-02-