Oracle Glossary: MAXVALUE

This parameter can be used in this situations as maximum value specified in a sequence declaration:
CREATE SEQUENCE …
MAXVALUE value
…..
can be used in flashback version query:
This keywords instruct Oracle to retrieve all available data versions.
The age of the data available is determined by the undo_retention
parameter
SELECT … fields …
FROM   … table …
VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE
WHERE  … conditions …