Thanks for reverting, but actually way/413446964/history at least needs to go one stage further back - locals here have said that it's "proposed", if that. See https://kitchener.citynews.ca/local-news/new-highway-7-between-kitchener-and-guelph-seemingly-snubbed-again-by-province-5158523 , apparently.

If they did, we've not seen the report yet, but we spotted the change, hence the thanks above.
Cheers,
Andy, from the DWG

You can do it in JOSM. I've done it in changeset/134305473 .

Also filled in some gaps and clipped some accidental spurs off NCN27.

Also cuts an accidental spur off. See https://overpass-turbo.eu/s/1t8l

Thanks for reverting!

https://osm.mapki.com/history/node/424314830
https://osm.mapki.com/history/node/1686293227
looks OK

relation/15654191 doesn't appear to be a statistical boundary

relation/15659596 appears not to be a statistical boundary either.

See note at https://community.openstreetmap.org/t/my-newly-uploaded-relation-15648965-is-not-being-located-by-nominatim/97409/8 . This isn't a statistical boundary,

@Allison P - thanks for the nudge. Perhaps Marek's email client is broken and he is not receiving emails? I have sent a message that he has to read before continuing to edit at osm.org/user_blocks/7000 so that he's aware of the issue.

Bonjour,
Il s'agissait essentiellement de votre première modification d'OpenStreetMap ; d'une manière générale, essayer de changer les frontières internationales n'est pas un bon premier changement dans OpenStreetMap.
Nous avons dû annuler vos modifications car elles ont rompu les relations ici.
Si vous avez des questions, veuillez envoyer un e-mail à [email protected] avec comme sujet "Re : [Ticket #2023032110000134] Sahara occidental"

Cordialement,
Andy

مرحبًا،
كان هذا في الأساس أول تعديل لك على OpenStreetMap ؛ بشكل عام ، فإن محاولة تغيير الحدود الدولية ليست تغييرًا جيدًا أولًا في OpenStreetMap.
لقد اضطررنا إلى التراجع عن تغييراتك لأنها قطعت العلاقات هنا.
إذا كان لديك أي أسئلة ، يرجى إرسال بريد إلكتروني إلى [email protected] مع موضوع "Re: [تذكرة رقم 2023032110000134] الصحراء الغربية"

أطيب التحيات،
آندي

Hello,
This was essentially your first edit to OpenStreetMap; generally speaking trying to change international borders is not a good first change in OpenStreetMap.
We've had to undo your changes as they have broken the relations here.
If you have any questions, please email [email protected] with a subject of "Re: [Ticket#2023032110000134] Western Sahara"

Best Regards,
Andy

Bonjour,
Pouvez-vous expliquer ce que vous essayez de faire ?
Cordialement,
Andy

Hello,
Can you explain what you are trying to do?
Best Regards,
Andy

Hello,
This was essentially your first edit to OpenStreetMap; generally speaking trying to change international borders is not a good first change in OpenStreetMap.
We've had to undo your changes as they have broken the relations here.
If you have any questions, please email [email protected] with a subject of "Re: [Ticket#2023032110000134] Western Sahara"

Best Regards,
Andy

Hello,
If it was me I'd just leave it as it is :)
Best Regards,
Andy

No panic - I only uploaded a photo as I was walking past.

See also note/3614396

Re "OSM wiki say that the key:natural should not be used on relations" - which wiki page says that?