[BUG] contentType

[mrentsch65]

Describe the bug
The explanation for contentType in 5.3.7.4 Blob Attributes is incorrect, it shouldn't talk about a file.

And in general the references to RFCs 2045 and 2046 are not optimal. RFC2045 is only of historical interest, whereas RFC2046 explains the principles. Especially missing is a reference to RFC2048 and the direct link to the resource with registered MediaTypes: https://www.iana.org/assignments/media-types/media-types.xhtml
I propose to improve and concentrate these explanations and references for ContentType in Table 8 and align the text in the BLOB section to the ones for Resource and File.

Where
Screenshots

[BirgitBoss]

I do not see a bug (except for the misleading "file" in the explanation of the contentType of a blob) but this I would consider to be minor, I only see proposals for improvement: what you are writing is already stated in the specification. Or I miss the main point...

[mrentsch65]

I was using the template. Fully agree, bug is a misclassification for this. Proposal for improvement fits indeed better. How can the label be changed?

[BirgitBoss]

I agree, we should add Reference to RFC2048 and add the link

RFC 2048 specified various IANA registration procedures for MIME-related facilities.
RFC 2046 specified the structure and syntax of MIME Media Types
The link to IANA https://www.iana.org/assignments/media-types/media-types.xhtml should stay.

We can remove this historical part.

Proposal for reformulation of ContentType:
https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/spec-metamodel/datatypes.html#ContentType

String with length 100 maximum
and minimum 1 characters

Any content type as specified in
RFC2046. 

The content type should be registered by the Internet Assigned Numbers Authority (IANA([link](https://www.iana.org/assignments/media-types/media-types.xhtml)))
 as specified in RFC2048. 

so this allows to also use mime types that are not registrered by IANA but follow the syntax as defined in RFC2046.

Remove
https://industrialdigitaltwin.io/aas-specifications/IDTA-01001/v3.1/spec-metamodel/submodel-elements.html#file-attributes

A media type (also MIME type and content type) is a two-part identifier for file formats and format contents transmitted via the Internet. The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication of these classifications.

[BirgitBoss]

TF Metamodel: proposal as described in #604 (comment) accepted

[mrentsch65]

In this context, please also have a look at "AssetInformation/defaultThumbnail", where Type was changed from "File" to "Resource"
What's the difference between File and Resource anyway? Some of the cardinality definitions look strange to me:

Couldn't this be unified for the sake of complexity reduction ?

[BirgitBoss]

In this context, please also have a look at "AssetInformation/defaultThumbnail", where Type was changed from "File" to "Resource" What's the difference between File and Resource anyway? Some of the cardinality definitions look strange to me:

Couldn't this be unified for the sake of complexity reduction ?

The main different between the two classes is

• File is a SubmodelElement inheriting semanticId and other features
• Resource is just a data type

In former version thumbnail was of type "File" but no SubmodelElement should be used in AAS metadata section. This is the reason we have two elements looking very similar on a first glance.

[BirgitBoss]

2025-09-11 Workstream AAS Specs
Proposal accepted