For example: https://polygon.io/docs/rest/options/contracts/all-contracts says:

underlying_ticker.gte
string
Search underlying_ticker for values that are greater than or equal to the given value.

when it should really be:

underlying_ticker_gte
string
Search underlying_ticker for values that are greater than or equal to the given value.

Other pages with similar error:
https://polygon.io/docs/rest/stocks/snapshots/unified-snapshot
https://polygon.io/docs/rest/options/snapshots/unified-snapshot

In general this doc bug occurs for ANY(?) query parameter (ticker, timestamp, strike_price, expiration_date, etc) that has a "filter modifier".

[Worse, I ran across python sample code in the docs that exhibited same error, but I can't seem to find that now.]