Out of curiosity, I downloaded that MS update from the link in the KB article; that fetched file "excel2010-kb4484164-fullfile-x86-glb.exe", sized 36.1 MB (!). I can confirm this is only SHA-2 code-signed:
You'll have to test file code-signing signatures in a fully updated Win7 system (or higher) or, in my case, in Vista SP2 with one of the WS2008SP2 updates which give the OS SHA-2 code-signing verification support...
Trying the Windows Update Catalog link (mentioned in that same KB article),
http://www.catalog.update.microsoft.com/Search.aspx?q=KB4484164
I ended up with a different file, excel-x-none_a5b150722cca4d6d9b062063747b02df0eaaaf51.cab (sized 19.8 MB); extracting it yields an excel-x-none.msp file (Windows Installer Patch, sized 40.3 MB), which is also only SHA-2 code-signed; notice that on the MUC, only a generic version is offered, regardless of the OS on which Office 2010 is installed ; perhaps the .exe and .msp files check OS version when launched, but it didn't occur to M$ that XP+Vista don't support SHA-2 code-signatures; there was a specific update on Vista (KB2763674) that allowed for .exe file execution even in the case the .exe was only SHA-2 signed, I guess a similar one might exist in XP (as part of the POSReady ones?) ...
The deal breaker here is that Windows Update on both XP and Vista was never patched to deliver updates signed with only sha-2 code signatures - for WS2008SP2, such an update does exist, but when that's installed on Vista, it changes the build number of Vista to 6.0.6003 - but that cuts off Vista completely from WU servers , because they were only configured to serve Vista 6.0.6002 builds; it emerges that WU servers are intelligent enough to tell apart Vista 6.0.6003 (blocked) from WS2008 6.0.6003 (supported); so, starting with Nov 2019 (and for the remaining updates till Oct 2020), users of Office 2010 SP2 on XP/Vista should manually install applicable updates from either MS Download Center/MUC...
( ... and you thought M$ would screw Office 2010 only on XP, by sending incompatible mso.dll files... )