I just noticed that the repo http://dl.google.com/linux/chrome/deb/

For years, the way that Google Chrome was updated on Ubuntu was via the repository As of now when I visit this URL I get a 404. Yet somehow Chrome appears to be at the latest version. Is Chrome being updated in some new way, perhaps by updating itself? Or is it blocking access via browser and wget?

1 Answer

TL;DR
This is intentional measure to protect APT repository from bots. Google does not have index document on the or URLs.
The repository itself is working normally. See analysis below.

Details
In Wireshark session on my Ubuntu MATE 18.04.3 LTS box I see that sudo apt-get update downloads the URL using Debian APT-HTTP/1.3 (1.6.14) user-agent.

So you can hack this out by "visiting" the mentioned URLs using "wget" as follows:

$ wget --spider --user-agent="Debian APT-HTTP/1.3 (1.6.14)"
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:07:18--
Resolving dl.google.com (dl.google.com)... 108.177.14.91, 108.177.14.136, 108.177.14.190, ...
Connecting to dl.google.com (dl.google.com)|108.177.14.91|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
Remote file does not exist -- broken link!!!

here 404 is confirmed.

But visiting the upper level URL gives redirect:

$ wget --spider --user-agent="Debian APT-HTTP/1.3 (1.6.14)"
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:09:34--
Resolving dl.google.com (dl.google.com)... 64.233.161.190, 64.233.161.93, 64.233.161.136, ...
Connecting to dl.google.com (dl.google.com)|64.233.161.190|:80... connected.
HTTP request sent, awaiting response... 302 Found
Location: [following]
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:09:34--
Resolving ()... 64.233.163.105, 64.233.163.106, 64.233.163.99, ...
Connecting to ()|64.233.163.105|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: [following]
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:09:34--
Connecting to ()|64.233.163.105|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: [following]
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:09:34--
Connecting to ()|64.233.163.105|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 301722 (295K) [text/html]
Remote file exists and could contain further links,
but recursion is disabled -- not retrieving.

From above HTTP conversation you can see the 302 redirect to which allows humans do download Google Chrome from official web-page.

Also you can try to access InRelease file using the same user-agent directly as follows:

$ wget --spider --user-agent="Debian APT-HTTP/1.3 (1.6.14)"
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:12:10-- >
Resolving dl.google.com (dl.google.com)... 64.233.161.190, 64.233.161.93, 64.233.161.136, ...
Connecting to dl.google.com (dl.google.com)|64.233.161.190|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1811 (1,8K) [application/octet-stream]
Remote file exists.

or even access the same file with default user-agent:

$ wget --spider
Spider mode enabled. Check if remote file exists.
--2022-02-13 10:15:18-- >
Resolving dl.google.com (dl.google.com)... 64.233.161.190, 64.233.161.93, 64.233.161.91, ...
Connecting to dl.google.com (dl.google.com)|64.233.161.190|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1811 (1,8K) [application/octet-stream]
Remote file exists.

So the 404 you get really means nothing for real use cases. APT needs other files which are normally available.