Text Presentation Sequences

[DanielGekeler]

Many emojis can be combined with VARIATION SELECTOR-15 to appear as a text variant. This forms a ED-8a text presentation sequence defined in UTS 51. Example: ⏳ -> ⏳︎

The definition of ED-8a states that the only valid sequences are those listed in emoji-variation-sequences.txt. These are also included in <standardized-variants> of UCD XML.

Let's get to the issue: 🎶 U+1F3B6 MULTIPLE MUSICAL NOTES Codepoints.net states that it can be combined with VS15 to get this: 🎶︎ even though it isn't listed in emoji-variation-sequences.txt. This character combined with VS15 seems to be widely supported even though it does not adhere to UTS 51.

How does Codepoints.net decide to show this notice?