New features

• feat: cuda reducers - add combinations for n>2, argmin and argmax, and fix min. by @ianna in #3645
• feat: add axis=None reducer specializations by @pfackeldey in #3653
• feat: add 'how=' to ak.unzip by @pfackeldey in #3655

Bug-fixes and performance

• fix: virtual array deep copy generator reference + better error message for assert_never by @ikrommyd in #3644
• fix: SVG bug in diagram depicting ragged aggregation by @jpivarski in #3648
• fix: json signedness fixes by @ianna in #3651
• fix: cartoon combinations by @ianna in #3654
• perf: detect & fastpath no-op range slices in all layout types by @pfackeldey in #3642

Other

• chore(deps): bump the actions group with 4 updates by @dependabot[bot] in #3650
• docs: fix touch_data typo by @ikrommyd in #3641
• docs: update CONTRIBUTING guidelines by @ianna in #3656

Full Changelog: v2.8.8...v2.8.9