Concept ACK.

It seems https://developer.apple.com just requires that one is logged in before following the https://download.developer.apple.com/Developer_Tools/Xcode_12.1/Xcode_12.1.xip link.

Concept ACK.
I always get a "403 Forbidden", also after being logged in.
Searching for "12.1" on https://developer.apple.com/download/all/ works.
I checked the sha256sum of my Xcode_12.1.xip file and got a match. 612443b1894b39368a596ea1607f30cbb0481ad44d5e29c75edb71a6d2cf050f

While touching this file, maybe update these lines as well

Or just drop them?

I think it would be useful to mention that cookies for https://download.developer.apple.com/ need to be allowed in order for the actual download link to work. Otherwise you could still login and click the download link and still get a 403.

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Conflicts

Reviewers, this pull request conflicts with the following ones:

• release: support cross-compiling for arm64-apple-darwin #21851 by fanquake

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

While touching this file, maybe update these lines as well
Or just drop them?

As mentioned afterward by Achow the link isn't dead, but needs cookies to be enabled. Edited to reflect that.

I think it would be useful to mention that cookies for https://download.developer.apple.com/ need to be allowed in order for the actual download link to work. Otherwise you could still login and click the download link and still get a 403.

Done.

so below is a diff and here is a branch with my suggestions

Thanks, took part of it for the english and formatting part.

Diff:

diff --git a/contrib/macdeploy/README.md b/contrib/macdeploy/README.md
index ad52f7d20e..cdf2b6609f 100644
--- a/contrib/macdeploy/README.md
+++ b/contrib/macdeploy/README.md
@@ -15,8 +15,10 @@ When complete, it will have produced `Bitcoin-Core.dmg`.
 Our current macOS SDK
 (`Xcode-12.1-12A7403-extracted-SDK-with-libcxx-headers.tar.gz`) can be
 extracted from
-[Xcode_12.1.xip](https://download.developer.apple.com/Developer_Tools/Xcode_12.1/Xcode_12.1.xip)
-(alternatively, after login to your account go to "Downloads", then "More" and look for [`Xcode_12.1`](https://download.developer.apple.com/Developer_Tools/Xcode_12.1/Xcode_12.1.xip)).
+[Xcode_12.1.xip](https://download.developer.apple.com/Developer_Tools/Xcode_12.1/Xcode_12.1.xip).
+Cookies must be enabled for this link to work after logging in.
+Alternatively, after logging in to your account go to 'Downloads', then 'More'
+and look for [`Xcode_12.1`](https://download.developer.apple.com/Developer_Tools/Xcode_12.1/Xcode_12.1.xip).
 An Apple ID is needed to download this.
 The `sha256sum` of the archive should be `612443b1894b39368a596ea1607f30cbb0481ad44d5e29c75edb71a6d2cf050f`.

While touching this file, maybe update these lines as well
Or just drop them?

As mentioned afterward by Achow the link isn't dead, but needs cookies to be enabled. Edited to reflect that.

Another link points at Xcode_11.3.1 but we use Xcode_12.1 for now.

Do we really need to link to the same xip from 3 different places in this README? Given that half the time the links don't even seem to work (they don't work for me now even when logged in), why not just remove them, or just have one.

As mentioned above, can you also update the instance of Xcode_11.3.1 further down, and remove the link there as well. There is some duplication of information in this file, but that doesn't have to be fixed here.

Do we really need to link to the same xip from 3 different places in this README?

No, i don't think so. I figured adding another link was helpful since it's what worked for me but i definitely don't have any opinion on how to rework this doc. This PR was just meant as a quick tiny link fix as i got through the process..