@alexhollender - seems like we have two options for logged-in users at least - display a modal that confirms they want to opt out and turn it off via the modal, or navigate them to their preferences page where they can turn off the setting. I think the first one is probably better, but the second option is what we use for page previews. Thoughts?

In T236176#5595572, @ovasileva wrote:

@alexhollender - seems like we have two options for logged-in users at least - display a modal that confirms they want to opt out and turn it off via the modal, or navigate them to their preferences page where they can turn off the setting. I think the first one is probably better, but the second option is what we use for page previews. Thoughts?

As we discussed the other day I think navigating them to the Appearance tab in settings will be sufficient. That way they also get to learn where the setting is located in case they want to switch it in the future.

ToggleSwitches should only be used in settings where instant effect is possible. Unlike AMC mode

Technical question: how will be the "Vector Legacy" skin and the new Vector separated?
Is it going to be a forked skin as suggested in T234907: RFC: Where to implement Desktop Improvements project Proposal 3?
Which repository will contain the old one? Will it be renamed to https://gerrit.wikimedia.org/r/mediawiki/skins/VectorLegacy, or the new one [[ https://gerrit.wikimedia.org/r/admin/projects/mediawiki/skins/VectorV2 | VectorV2 ]] (there is one already)? Or is it going to be a branch, which I assume would cause some difficulties to operators unfamiliar with git (branches).

Hi @AronManning! Per the outcome of T234907, development is already underway in Vector itself. My understanding is that this approach will allow us to minimize development costs. The existing experience (now called "legacy") will be carefully preserved via a user preference (the subject of this task) and feature manager.

In T236176#5827176, @Niedzielski wrote:

The existing experience (now called "legacy") will be carefully preserved via a user preference (the subject of this task) and feature manager.

Thank you! I missed that part that a final decision has been made (confirmation bias on my part). I think the hard part in "carefully preserving" the legacy mode will be the branching in the code itself, while implementing the user setting is the easy part. I'd like to better understand the former. As I haven't yet seen how this will manifest in code, I have the superficial presumption this might turn into a lot of branches and a more intertwined code, on the other hand, if cleanup steps are also applied to the Legacy Vector, it might even be beneficial.

Could you, or somebody familiar with the commits link to code that shows how this branching is done in practice, so I can better understand?

@AronManning, I think a good place to start would be FeaturesManager.php in MobileFrontend and the contents of the features subdirectory. An example mode implementation would be the AMC UserMode (this class represents advanced mode on mobile--the name is a relic from when it was called Advanced Mobile Contributions) and an example feature would be the standard and advanced menus. More details in T242835.