Quire.com

project management, collaborationware, task manager - https://quire.io/

their Free level still supports collaboration https://quire.io/pricing

Mar'2023 trying it out

• mainly because it has infinite hierarchy of tasks
  • cf Graph-Driven SoftwareForge
• can't add stream of notes to an item, just a single Description field to edit
• no link on task, have to stuff that in Description too