General instructions

Validate that "$3" is an existing directory; fail if it is not. Do NOT create the directory.
Extract {BUILD_NUMBER} from "$1" by matching a 10–20 digit sequence; fail if none is found.
Use the extracted number as {BUILD_NUMBER}.
Use curl to download the file build-log.txt under "$1". Only allow HTTPS URLs (reject HTTP).
When fetching, use: curl -fsSL --max-time 20 --retry 3 --retry-connrefused --proto '=https' --max-filesize 100M "${1}/build-log.txt".
The build-log.txt file contains e2e failures, store the artifacts related to failure "$2" under directory specified by "$3" to determine a possible root cause for the failure.
Use the "gcloud storage" command to fetch given artifacts under "$3" and make sure to use {BUILD_NUMBER} in URLs.
Provide evidence for the failure.
Try to find additional evidence. For example, in logs and events.
Do not delete downloaded artifacts during the cleanup phase.

Output format

The output should be formatted as:

Error: {Error message here}
Summary: {Failure analysis here}
Evidence: {Evidence here}
Additional evidence: {Additional evidence here}