Currently in chrome source:

$ gn gen '--args=use_libfuzzer=true is_asan=true enable_nacl=false' --check out/fuzzer

$ gn refs out/fuzzer --as=label //testing/libfuzzer:seed_corpus
//third_party/boringssl:boringssl_client_bio_write_fuzzer_seed_corpus
//third_party/boringssl:boringssl_d2i_autoprivatekey_fuzzer_seed_corpus
//third_party/boringssl:boringssl_d2i_x509_fuzzer_seed_corpus
//third_party/boringssl:boringssl_server_bio_write_fuzzer_seed_corpus

$ gn desc out/fuzzer //third_party/boringssl:boringssl_client_bio_write_fuzzer_seed_corpus
Target: //third_party/boringssl:boringssl_client_bio_write_fuzzer_seed_corpus
Type: Action
Toolchain: //build/toolchain/linux:clang_x64

visibility:
  *

script:
  //testing/libfuzzer/archive_corpus.py

args:
  --depfile
  /usr/local/google/home/aizatsky/src/chrome/src/out/fuzzer/boringssl_client_bio_write_fuzzer.seed_corpus.d
  --corpus
  /usr/local/google/home/aizatsky/src/chrome/src/third_party/boringssl/src/fuzz/client_corpus
  --output
  /usr/local/google/home/aizatsky/src/chrome/src/out/fuzzer/boringssl_client_bio_write_fuzzer_seed_corpus.zip
  --fuzzer
  /usr/local/google/home/aizatsky/src/chrome/src/out/fuzzer/boringssl_client_bio_write_fuzzer_seed_corpus

depfile:
  //out/fuzzer/boringssl_client_bio_write_fuzzer.seed_corpus.d

outputs:
  //out/fuzzer/boringssl_client_bio_write_fuzzer_seed_corpus.zip

Direct dependencies (try also "--all", "--tree", or even "--all --tree"):
  //testing/libfuzzer:seed_corpus


BUT:

$ gn refs out/fuzzer --as=output //testing/libfuzzer:seed_corpus
obj/third_party/boringssl/boringssl_d2i_x509_fuzzer_seed_corpus.stamp
obj/third_party/boringssl/boringssl_client_bio_write_fuzzer_seed_corpus.stamp
obj/third_party/boringssl/boringssl_d2i_autoprivatekey_fuzzer_seed_corpus.stamp
obj/third_party/boringssl/boringssl_server_bio_write_fuzzer_seed_corpus.stamp


I believe the last command should list boringssl_client_bio_write_fuzzer_seed_corpus.zip instead of .stamp file.