mei:unclear

Signifies the causative agent of damage, illegibility, or other loss of
original text.

Signifies the degree of certainty or precision associated with a
feature.

Indicates the nature of the evidence supporting the reliability or
accuracy of the intervention or interpretation. Suggested values include: 'internal',
'external', 'conjecture'.

Permits the current element to reference a facsimile surface or image zone
which corresponds to it.

Signifies the hand responsible for an action. The value must be the ID of
a <hand> element declared in the header.

Provides a name or label for an element. The value may be any
string.

Provides a number-like designation for an element.

Holds a short phrase describing the reason for missing textual material
(gap), why material is supplied (supplied), or why transcription is difficult
(unclear).

Indicates the agent(s) responsible for some aspect of the text's creation,
transcription, editing, or encoding. Its value must point to one or more identifiers
declared in the document header.

Contains a list of one or more pointers indicating the sources which
attest to a given reading. Each value should correspond to the ID of a <source>
element located in the document header.

Specifies the transliteration technique used.

Provides a base URI reference with which applications can resolve relative
URI references into absolute URI references.

Regularizes the naming of an element and thus facilitates building links
between it and other resources. Each id attribute within a document must have a unique
value.

Identifies the language of the element's content. The values for this
attribute are language 'tags' as defined in BCP 47. All language tags that make use of
private use sub-tags must be documented in a corresponding language element in the MEI
header whose id attribute is the same as the language tag's value.