What does the word fork tell you?
A fork can describe copied software or a change to network rules. Those are different events. Ask which meaning a writer intends before assuming that a new name shares Bitcoin’s history.
Source: Consensus rule changes
How do soft forks and hard forks differ?
A soft fork tightens accepted rules: blocks following the tighter rules remain within what older nodes accept. Upgraded nodes enforce the extra restrictions.
A hard fork changes rules so some blocks accepted under the new rules may be rejected by nodes using the old rules. If both groups keep participating, separate chains can continue. A rule change alone does not guarantee a lasting split.
Which splits are shown in the family tree?
Bitcoin Cash (BCH) split from Bitcoin on 1 August 2017, mainly over block size. Bitcoin SV (BSV) split from Bitcoin Cash in November 2018. BTC, BCH and BSV are separate assets.
See the full family diagram to distinguish these splits from the separately described Bitcoin Ecosystem family.
What should you check about a fork?
Check the public code, its origin, network parameters and issuance rules. Compare the description with node releases and a working explorer. Shared code does not settle questions about custody or governance.
A fork coin has its own market, software and risks. Holding BTC does not make a fork coin safe to claim or use. Sharing private keys to claim an unfamiliar asset can expose funds.
Source: Bitcoin developer guide