If you want to change, OK, BUT please normalise to use lowercase for the 'calendar' as this does NOT depend on English Grammar: it is the Type of the field in code.
Therefore, should be:
PLG_FIELDS_CALENDAR_XML_DESCRIPTION="This plugin lets you create new fields of type 'calendar' in any extensions where custom fields are supported."

This is what we have done for all PLG_FIELDS_

Example in French, we do not translate 'calendar':
PLG_FIELDS_CALENDAR_XML_DESCRIPTION="Ce plugin permet de créer de nouveaux champs de type 'calendar' dans les extensions où les champs personnalisés sont implémentés."

Found "No newline at end of file" in below file:

• administrator/language/en-GB/en-GB.plg_fields_color.ini
• administrator/language/en-GB/en-GB.plg_fields_color.sys.ini

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@infograf768 updated to use lowercase for calendar even though it was beyond the scope of this PR as it was originally committed incorrectly - I guess you didn't spot it before ;)

@RonakParmar done

I have tested this item ✅ successfully on 480296b

Done code review.

I guess you didn't spot it before

It was indeed modified in a more recent committed PR and yep, I did not spot that one.

It was modified here:
#13638

while it was correct here:
#13710

I'm good with this too so merged :)