Yes, and the tz database handles this. (In fact the most immediate trigger for the 2021b release is that Samoa decided to get rid of daylight savings, but obviously did not retroactively change any times in the past... which points to an obvious constraint on that definition, you can specify the starting time where the definition is valid, but you cannot specify the ending time unless you can predict the future behavior of all governments worldwide. There have been tzdata releases with about a day to spare.)
In the past, most cities set their noon to actual solar noon, and when rail travel and communications made them pick a time relative to GMT, for a time they specified solar noon in GMT. For instance, America/New_York in the late 1800s gets you GMT-4:56, because that's what was actually used.
The rule for the tz database is that if two legislative time zones have the same definition from 1970 onwards, they might only represent them as a single time zone in the database. For instance, there's no America/Miami distinct from America/New_York, even though solar noon is a couple minutes different.
As it happens, Oslo and Berlin are the same from 1970 onwards, but the tz database currently has distinct Europe/Oslo and Europe/Berlin definitions. The proposal is to get rid of that distinction.
What if Oslo or Berlin vote to change their time zones, though? What if Norway pulls out of the EU in a "Nexit" referendum and then changes their DST to suit their economy? Wouldn't it be worth keeping the distinct Oslo and Berlin time zones?
Well, the same thing could happen to Miami, and there's no America/Miami at all right now. There's no sense defining every possible location in the world as a time zone to future-proof against that. It would have to be defined in a future version of the database.
In the past, most cities set their noon to actual solar noon, and when rail travel and communications made them pick a time relative to GMT, for a time they specified solar noon in GMT. For instance, America/New_York in the late 1800s gets you GMT-4:56, because that's what was actually used.
The rule for the tz database is that if two legislative time zones have the same definition from 1970 onwards, they might only represent them as a single time zone in the database. For instance, there's no America/Miami distinct from America/New_York, even though solar noon is a couple minutes different.
As it happens, Oslo and Berlin are the same from 1970 onwards, but the tz database currently has distinct Europe/Oslo and Europe/Berlin definitions. The proposal is to get rid of that distinction.
What if Oslo or Berlin vote to change their time zones, though? What if Norway pulls out of the EU in a "Nexit" referendum and then changes their DST to suit their economy? Wouldn't it be worth keeping the distinct Oslo and Berlin time zones?
Well, the same thing could happen to Miami, and there's no America/Miami at all right now. There's no sense defining every possible location in the world as a time zone to future-proof against that. It would have to be defined in a future version of the database.