Drop all MobileFrontend code supporting the legacy parser
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Authored By

	Jdlrobson-WMF
	Mar 27 2026, 9:45 PM

Description

Background

When Parsoid is the default for mobile (T422543: Deploy Parsoid Read Views to MobileFrontEnd readers on enwiki) the Readers Growth team will need to determine what support level they want to give the legacy parser in MobileFrontend and for how long.

Removing support for the legacy parser, will remove section collapsing and lazy loaded images but will remove many thousand lines of code.

User story

Add user story in the format: “As a [persona], I want to [X], so that [Y]”

Requirements

Decide level of support for legacy parser
delete or deprecate unnecessary code.

BDD

For QA engineer to fill out

Test Steps

For QA engineer to fill out

Design

Add mockups and design requirements

Acceptance criteria

Add acceptance criteria

Communication criteria - does this need an announcement or discussion?

Add communication criteria

Rollback plan

What is the rollback plan in production for this task if something goes wrong?

This task was created by Version 1.2.0 of the Web team task template using phabulous

Details

Related Changes in Gerrit:

	Subject	Repo	Branch	Lines +/-
	POC: Drop legacy parser related code	mediawiki/extensions/MobileFrontend	master	+16 -2 K

Customize query in gerrit

Related Objects

Mentioned In: T422466: Images shrink / resize on page scrolling in mobile view
Mentioned Here: T422543: Deploy Parsoid Read Views to MobileFrontEnd readers on enwiki

Event Timeline

Jdlrobson-WMF created this task.Mar 27 2026, 9:45 PM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptMar 27 2026, 9:45 PM

Jdlrobson-WMF triaged this task as Low priority.Mar 27 2026, 9:45 PM

Jdlrobson-WMF moved this task from Post Parsoid roll out to Post Parsoid roll out (decline) on the Readers Essential Work (WE6.3.4 Fix bugs within the reading experience across platforms for Parsoid Read Views) board.

taavi added a project: MobileFrontend.Mar 27 2026, 9:46 PM

Jdlrobson-WMF moved this task from Post Parsoid roll out (decline) to Post Parsoid roll out on the Readers Essential Work (WE6.3.4 Fix bugs within the reading experience across platforms for Parsoid Read Views) board.Mar 27 2026, 9:46 PM

Change #1235440 had a related patch set uploaded (by Jdlrobson; author: Jdlrobson):

[mediawiki/extensions/MobileFrontend@master] POC: Drop legacy parser related code

https://gerrit.wikimedia.org/r/1235440

Change #1235440 abandoned by Jdlrobson:

[mediawiki/extensions/MobileFrontend@master] POC: Drop legacy parser related code

Reason:

To be revisited post-Parsoid deployed everywhere https://phabricator.wikimedia.org/T421550

https://gerrit.wikimedia.org/r/1235440

Maintenance_bot removed a project: Patch-For-Review.Mar 27 2026, 10:30 PM

Izno subscribed.Mar 28 2026, 12:08 AM

Jdlrobson-WMF moved this task from WE6.3.4 Fix bugs within the reading experience across platforms for Parsoid Read Views to Simplify MobileFrontend on the Readers Essential Work board.Apr 7 2026, 4:00 PM

Jdlrobson-WMF edited projects, added Readers Essential Work (Simplify MobileFrontend); removed Readers Essential Work (WE6.3.4 Fix bugs within the reading experience across platforms for Parsoid Read Views).

Jdlrobson-WMF updated the task description. (Show Details)Apr 7 2026, 11:16 PM

Jdlrobson-WMF moved this task from Untriaged to MobileFormatter on the MobileFrontend board.Apr 7 2026, 11:19 PM

Jdlrobson-WMF edited projects, added MobileFrontend (MobileFormatter); removed MobileFrontend.

Jdlrobson-WMF mentioned this in T422466: Images shrink / resize on page scrolling in mobile view.Apr 7 2026, 11:36 PM

Johannnes89 subscribed.Apr 8 2026, 5:26 AM

Jdlrobson-WMF moved this task from Backlog to Post-Parsoid migration on the Readers Essential Work (Simplify MobileFrontend) board.Mon, Apr 27, 5:52 PM

Drop all MobileFrontend code supporting the legacy parserOpen, LowPublicActions