[BUG]: Publish Windows Symbols Warning for Unsupported source provider 'GitHub'

[pasuparthy-vishnu]

New issue checklist

• I searched for existing GitHub issues
• I read pipeline troubleshooting guide
• I checked how to collect logs

Task name

PublishSymbols@2

Task version

No response

Issue Description

We have recently migrated our ADO Repository to GitHub Proxima. Our Sourcecode live in GH and pipeline still reside in ADO and when running the PullRequest pipeline I see this error
##[warning]Unsupported source provider ‘GitHub’ for source indexing. ##[warning]Unable to index sources

Environment type (Please select at least one enviroment where you face this issue)

• Self-Hosted
• Microsoft Hosted
• VMSS Pool
• Container

Azure DevOps Server type

dev.azure.com (formerly visualstudio.com)

Azure DevOps Server Version (if applicable)

No response

Operation system

Windows

Relevant log output

Starting: 🔒 Publish Windows Symbols
==============================================================================
Task         : Index sources and publish symbols
Description  : Index your source code and publish symbols to a file share or Azure Artifacts symbol server
Version      : 2.260.0
Author       : Microsoft Corporation
Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/build/index-sources-publish-symbols
==============================================================================
Found 4 files.
##[warning]Unsupported source provider 'GitHub' for source indexing.
##[warning]Unable to index sources.
Symbol Request Name = finops/dev-cssamplerepo-pullrequest/1.0.03145.244-35039a06/133636972/510f3e7a-f544-424e-9c62-c27d768b9c84
Added TLS 1.2 in session.
Symbol Request Name = 
Get the access token
Get-AccessToken -ConnectedServiceName  -AsAccountName microsoft -UseAad False
PAT access token
Received PersonalAccessToken: ***
C:\ToolCache\VSOSymbolClient\20.259.36311.8.87edf10207\symbol.app.buildtask.complete not found
Creating C:\ToolCache\VSOSymbolClient\20.259.36311.8.87edf10207
C:\ToolCache\VSOSymbolClient\20.259.36311.8.87edf10207
Update complete
"C:\ToolCache\VSOSymbolClient\20.259.36311.8.87edf10207\lib\net45\symbol.exe" publish --service "https://microsoft.artifacts.visualstudio.com" --name "finops/dev-cssamplerepo-pullrequest/1.0.03145.244-35039a06/133636972/510f3e7a-f544-424e-9c62-c27d768b9c84" --directory "D:\a\_work\1\s\out" --expirationInDays "7" --patAuthEnvVar SYMBOL_PAT_AUTH_TOKEN --fileListFileName "C:\Users\cloudtest\AppData\Local\Temp\tmp28F3.tmp" --indexableFileFormats ""Default"" --tracelevel verbose --globalretrycount 2
[Symbol App][VERBOSE] 2025-08-12T23:43:18.4412633+00:00  Version: 20.259.36311.8 built by: releases/M259 (87edf10207)
[Symbol App][VERBOSE] 2025-08-12T23:43:18.4568893+00:00  Commandline: "C:\ToolCache\VSOSymbolClient\20.259.36311.8.87edf10207\lib\net45\symbol.exe"  
[Symbol App][VERBOSE] 2025-08-12T23:43:18.4568893+00:00  Environment: DotNetReleaseDword=528449
[Symbol App][VERBOSE] 2025-08-12T23:43:18.4568893+00:00  Performing operation...
[Symbol App][INFO]    2025-08-12T23:43:18.5818827+00:00  ApplicationInsightsTelemetrySender will correlate events with X-TFS-Session 7e88984a-932c-464f-91ed-d287066759a8
[Symbol App][VERBOSE] 2025-08-12T23:43:18.5818827+00:00  Started ITelemetrySender ApplicationInsightsTelemetrySender.
[Symbol App][VERBOSE] 2025-08-12T23:43:18.5975045+00:00  PublishOperation starting
[Symbol App][VERBOSE] 2025-08-12T23:43:18.6131330+00:00  Authenticating with PAT
[Symbol App][VERBOSE] 2025-08-12T23:43:18.6131330+00:00  Credentials acquired
[Symbol App][VERBOSE] 2025-08-12T23:43:18.6601553+00:00  ArtifactHttpClientFactory.CreateVssHttpClient: SymbolHttpClient with BaseUri: https://microsoft.artifacts.visualstudio.com/, MaxRetries:5, SendTimeout:00:10:00
[Symbol App][VERBOSE] 2025-08-12T23:43:18.7694099+00:00  ArtifactHttpClientFactory.VerifyConnectionAsync: SymbolHttpClient.GetOptionsAsync starting
[Symbol App][VERBOSE] 2025-08-12T23:43:19.1913453+00:00  ArtifactHttpClientFactory.VerifyConnectionAsync: SymbolHttpClient.GetOptionsAsync completed with InitialRequestSucceeded
[Symbol App][VERBOSE] 2025-08-12T23:43:19.2069131+00:00  Symbol.CreateRequestAsync starting
[Symbol App][VERBOSE] 2025-08-12T23:43:19.3631675+00:00  Symbol.CreateRequestAsync completed in 0.153957 seconds
[Symbol App][INFO]    2025-08-12T23:43:19.3788703+00:00  Request 'finops/dev-cssamplerepo-pullrequest/1.0.03145.244-35039a06/133636972/510f3e7a-f544-424e-9c62-c27d768b9c84' has been assigned Id '4279563db2ea1c9fa20bd4deba393cbb38b752dc34f5dcb2bd0356470b89653c'
[Symbol App][VERBOSE] 2025-08-12T23:43:19.3788703+00:00  Symbol.PublishFilesAsync starting
[Symbol App][VERBOSE] 2025-08-12T23:43:19.5506753+00:00  Symbol.GetRequestAsync starting
[Symbol App][VERBOSE] 2025-08-12T23:43:19.6131795+00:00  Symbol.GetRequestAsync completed in 0.0595463 seconds

Full task logs with system.debug enabled

Details

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Repro steps

[v-schhabra]

@carl-tanner @kunalkaroth Could you pls check this issue as you are owning this task?