Below are examples of how to set up a proxy using the Local API Clients in different programming languages:

For Javascript:

const createProfileRequest = BuilderForCreateProfile
  .forBaseProfile(chromeBaseProfileList[0].id)
  .setRecommendedDefaults()
  .setWebglMeta(
    'manual',
    {
      vendor: 'Google Inc. (AMD)',
      renderer: 'ANGLE (AMD Radeaon (TM) RX 560 Direct3D11 vs_5_0),
    },
  )
  .build();
const profile = await client.createProfile({ body: createProfileRequest });

For Python:

create_profile_request = BuilderForCreateProfile 
  .for_base_profile(base_profiles[0].id) 
  .set_recommended_defaults() 
  .set_webgl_meta('manual', WebglMetaSpoofingOptions(vendor='Google Inc. (AMD)', renderer='ANGLE (AMD Radeaon (TM) RX 560 Direct3D11 vs_5_0)')) 
  .build()
profile = client.create_profile(body=create_profile_request)

These answers are provided from the Kameleo Set WebGL Metadata from API article.