These entries are queried from radb.net using whois, you can try my project getting these.
:AS31377 route: 23.1.0.0/22 descr: Akamai Technologies origin: AS31377 mnt-by: AKAM1-ALTDB-MNT changed: ip-admin [at] akamai.com 20190628 source: ALTDB rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.1.0.0/24 descr: Akamai Technologies origin: AS31377 mnt-by: MNT-AKAMAI source: ARIN changed: ip-admin [at] akamai.com 20200226 rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.1.1.0/24 descr: Akamai Technologies origin: AS31377 mnt-by: MNT-AKAMAI source: ARIN changed: ip-admin [at] akamai.com 20200226 rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.1.2.0/24 descr: Akamai Technologies origin: AS31377 mnt-by: MNT-AKAMAI source: ARIN changed: ip-admin [at] akamai.com 20200226 rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.1.3.0/24 descr: Akamai Technologies origin: AS31377 mnt-by: MNT-AKAMAI source: ARIN changed: ip-admin [at] akamai.com 20200304 rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.48.0.0/13 descr: Akamai Technologies, Inc. origin: AS31377 mnt-by: AKAM1-ALTDB-MNT changed: marty [at] akamai.com 20110516 source: ALTDB rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.192.0.0/12 descr: Akamai Technologies origin: AS31377 mnt-by: AKAM1-ALTDB-MNT changed: jzipkin [at] akamai.com 20120715 source: ALTDB rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source route: 23.208.0.0/14 descr: Akamai Technologies origin: AS31377 mnt-by: AKAM1-ALTDB-MNT changed: jzipkin [at] akamai.com 20120715 source: ALTDB rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source