awesome-safety-critical lists a number of Handbooks, but not yet this one. https://awesome-safety-critical.readthedocs.io/en/latest/ :

> NASA-GB-8719.13 - 2004-03-31 - NASA Software Safety Guidebook

>> NASA’s Software Safety Guidebook (pdf file). The handbook complement to the Software Safety Standard.

> NASA-HDBK-8709.24 - 2015-11-23 - NASA Safety Culture Handbook