What is the Gemini API's grounded generation with Google Search and how does attribution work?

from google import genai
from google.genai import types

client = genai.Client()

response = client.models.generate_content(
    model="gemini-3.5-flash",
    contents="What are the most recent Gemini API updates?",
    config=types.GenerateContentConfig(
        tools=[types.Tool(google_search=types.GoogleSearch())],
    )
)

print(response.text)

# Access grounding metadata:
candidate = response.candidates[0]
if candidate.grounding_metadata:
    gm = candidate.grounding_metadata

    # Sources used:
    print("\nSources:")
    for chunk in gm.grounding_chunks:
        if chunk.web:
            print(f"  - {chunk.web.title}: {chunk.web.uri}")

    # Which parts of the response are grounded:
    for support in gm.grounding_supports:
        text_segment = support.segment.text
        sources = [gm.grounding_chunks[i].web.uri
                   for i in support.grounding_chunk_indices]
        print(f"\nClaim: {text_segment[:80]}...")
        print(f"Supported by: {sources}")

    # Search entry point (rendered search suggestion UI element):
    if gm.search_entry_point:
        print(f"\nSearch UI: {gm.search_entry_point.rendered_content[:100]}")