Tested the issue on chrome reported version 65.0.3325.162 using Windows-10 with steps mentioned below:
1) Launched chrome reported version and installed around 15 extensions 
2) Opened chrome://extensions, able to see all the extensions installed

@Reporter: Please find the attached screen cast for your reference and let us know if we missed anything in reproducing the issue, provide your feedback on it which help in further triaging it.

Thanks!

Deleted: 822939.mp4 3.1 MB

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Assigning to ddorwin to provide more info on how to reproduce this.

I probably have 30 extensions (most disabled) and 10+ apps installed, so 15 might not be enough. Currently, 17 are shown and that just gets to "Google..." Refreshing showed 21 and was at "Gu..."

You might want to install 20 more extensions and disable a bunch. Note that I also have apps installed, which you do not appear to have. While I don't think this is OS-specific, note that you used Windows, while I used Mac and Linux.

I am trying to reproduce with a 21 extensions + 15 apps, without success (also on Linux). See attached video.

@ddorwin:
 1) Can you verify that there is nothing typed in the searchbox (just a sanity check that you are not seeing a filtered list).
 2) Do you see the same issue if you switch back to the old page (turn off chrome://flags/#enable-md-extensions).

There seems to be something going on, on your machine that is not captured in the repro steps.

Deleted: extensions_list.mp4 6.8 MB

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Perhaps one of your "disabled" extensions is actually blacklisted, and this would be a duplicate of  issue 823164 . 

I don't think I'd have any blacklisted extensions, but reading that bug did cause me to look at the console, which contains an error on both computers:

polymer-mini-extracted.js:2128 Uncaught Error: VIDEO is not supported
    at assertElement (crisper.js:116)
    at crisper.js:116
    at walk (crisper.js:116)
    at walk (crisper.js:116)
    at walk (crisper.js:116)
    at crisper.js:116
    at HTMLElement.i18n (crisper.js:120)
    at HTMLElement.a11yAssociation_ (crisper.js:124)
    at HTMLElement._annotatedComputationEffect (polymer-extracted.js:1634)
    at HTMLElement._effectEffects (polymer-extracted.js:1443)

That is followed by a very long stack, which contains some of same path as  issue 823164 . I've attached the full thing.

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The error is most likely coming from [1]. Do you have any idea how does a <video> tag end up on your page? This looks suspicious.


[1] https://cs.chromium.org/chromium/src/ui/webui/resources/js/parse_html_subset.js?dr&l=61,86

+hcarmona

The only place where a11yAssociation is used is at https://cs.chromium.org/chromium/src/chrome/browser/resources/md_extensions/item.html?type=cs&q=a11yAssociation_&l=217.

It seems that you have an extension that has HTML code inside the name of it?

dpapad@'s assessment is correct. Looks like an extension with some HTML in the name can break the page. Unzip attached extension and load in developer mode to break extension page. (Or don't since it will kill the page as described in the bug)

I can upload a CL to fix for this right now. Will add dpapad@ as reviewer.

Deleted: broken.zip 411 bytes

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+rdevlin.cronin
@hcarmona: Before fixing, let's determine if this is necessary. What does the old UI do in this case?

[1] https://cs.chromium.org/chromium/src/ui/webui/resources/js/parse_html_subset.js?dr&l=36

OLD UI loads without issue.

Deleted: old extension page.png 60.4 KB

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So, old UI does not face this problem because it never passes the extension name through localization, see [1]. The new UI tries to construct a string "Related to <extension_name_here>" for a11y purposes at [2], which is what causes the different behavior between old and new.

Moreover, name and short_name fields are described at [3], and it seems that there are no restrictions on which characters can be used in the name (and assuming no C++ side validation).

@rdevlin.cronin: Do you know if allowing HTML code for an extension's name is intentional?


[1] https://cs.chromium.org/chromium/src/chrome/browser/resources/extensions/extension_list.js?l=620,939
[2] https://cs.chromium.org/chromium/src/chrome/browser/resources/md_extensions/item.js?l=112
[3] https://developer.chrome.com/extensions/manifest/name

Yes, I have a disabled extension with `<video>/<audio>` at the end of the name.

> @rdevlin.cronin: Do you know if allowing HTML code for an extension's name is intentional?

For cases like this (having "<video>" in the name), I think it's acceptable.  Even if we wanted to forbid it, we could still be tripped up by something as simple as a > character.  I think sanitization here is definitely the right answer.

Just to confirm, I removed the extension using the old UI, and now all my extensions are shown in the new MD UI.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/195ae3b61e790d20baf998b4926556db939febec

commit 195ae3b61e790d20baf998b4926556db939febec
Author: Hector Carmona <hcarmona@chromium.org>
Date: Fri Mar 30 05:26:21 2018

MD Extensions: Fix overly aggressive sanitation.

Polymer already protects against XSS injection, we just need to
combine the two strings.

Bug:  822939 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I866d65419b22d63a1c5a460f6a30304e4a5d487a
Reviewed-on: https://chromium-review.googlesource.com/981599
Commit-Queue: Hector Carmona <hcarmona@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547113}
[modify] https://crrev.com/195ae3b61e790d20baf998b4926556db939febec/chrome/browser/resources/md_extensions/item.js
[modify] https://crrev.com/195ae3b61e790d20baf998b4926556db939febec/chrome/test/data/webui/extensions/cr_extensions_browsertest.js
[modify] https://crrev.com/195ae3b61e790d20baf998b4926556db939febec/chrome/test/data/webui/extensions/extension_item_test.js

Likely we'll want to merge this to 66 as well, yeah?

This bug requires manual review: M66 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), josafat@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Approving merge to M66. Branch:3359

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c22378c52caaf023107dd5976d869cd48529bde7

commit c22378c52caaf023107dd5976d869cd48529bde7
Author: Hector Carmona <hcarmona@chromium.org>
Date: Mon Apr 02 18:00:07 2018

MD Extensions: Fix overly aggressive sanitation.

Polymer already protects against XSS injection, we just need to
combine the two strings.

Bug:  822939 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I866d65419b22d63a1c5a460f6a30304e4a5d487a
Reviewed-on: https://chromium-review.googlesource.com/981599
Commit-Queue: Hector Carmona <hcarmona@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#547113}(cherry picked from commit 195ae3b61e790d20baf998b4926556db939febec)
Reviewed-on: https://chromium-review.googlesource.com/990312
Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Cr-Commit-Position: refs/branch-heads/3359@{#529}
Cr-Branched-From: 66afc5e5d10127546cc4b98b9117aff588b5e66b-refs/heads/master@{#540276}
[modify] https://crrev.com/c22378c52caaf023107dd5976d869cd48529bde7/chrome/browser/resources/md_extensions/item.js
[modify] https://crrev.com/c22378c52caaf023107dd5976d869cd48529bde7/chrome/test/data/webui/extensions/cr_extensions_browsertest.js
[modify] https://crrev.com/c22378c52caaf023107dd5976d869cd48529bde7/chrome/test/data/webui/extensions/extension_item_test.js