In A Portrait of VSCode's external contributors we analyzed internal vs external contributors to VSCode using the vscode.sql script here.
You can run build-the-script.py with other settings to analyze another repo. The example provided is for TypeScript (typescript.sql), where we found:
select count(*), 'internal' as type from typescript_internal_committers
union
select count(*), 'external' as type from typescript_external_committers;
count | type
-------+----------
54 | internal
540 | external
select count(*), 'internal' as type from typescript_internal_issue_filers
union
select count(*), 'external' as type from typescript_external_issue_filers;
count | type
-------+----------
118 | internal
10670 | external
select * from typescript_internal_commit_counts limit 10;
repository_full_name | author_login | count
----------------------+-------------------+-------
microsoft/typescript | ahejlsberg | 3690
microsoft/typescript | sheetalkamat | 2600
microsoft/typescript | DanielRosenwasser | 2269
microsoft/typescript | sandersn | 2209
microsoft/typescript | andy-ms | 2067
microsoft/typescript | rbuckton | 1708
microsoft/typescript | weswigham | 1503
microsoft/typescript | RyanCavanaugh | 915
microsoft/typescript | typescript-bot | 468
microsoft/typescript | amcasey | 466
select * from typescript_external_commit_counts limit 10;
repository_full_name | author_login | count
----------------------+-----------------+-------
microsoft/typescript | JsonFreeman | 674
microsoft/typescript | a-tarasyuk | 508
microsoft/typescript | zhengbli | 468
microsoft/typescript | yuit | 217
microsoft/typescript | saschanaz | 215
microsoft/typescript | Kingwl | 202
microsoft/typescript | ajafff | 180
microsoft/typescript | tinganho | 99
microsoft/typescript | JoshuaKGoldberg | 87
microsoft/typescript | bigaru | 77
select * from typescript_internal_issue_counts limit 10;
repository_full_name | author_login | count
----------------------+-------------------+-------
microsoft/typescript | danielrosenwasser | 1192
microsoft/typescript | ryancavanaugh | 318
microsoft/typescript | sandersn | 296
microsoft/typescript | dbaeumer | 249
microsoft/typescript | weswigham | 199
microsoft/typescript | amcasey | 139
microsoft/typescript | rbuckton | 106
microsoft/typescript | egamma | 96
microsoft/typescript | sheetalkamat | 69
microsoft/typescript | jrieken | 60
select * from typescript_external_issue_counts limit 10;
repository_full_name | author_login | count
----------------------+------------------+-------
microsoft/typescript | falsandtru | 439
microsoft/typescript | zpdDG4gta8XKpMCd | 310
microsoft/typescript | OliverJAsh | 245
microsoft/typescript | ajafff | 220
microsoft/typescript | JsonFreeman | 156
microsoft/typescript | tinganho | 151
microsoft/typescript | saschanaz | 133
microsoft/typescript | basarat | 130
microsoft/typescript | NoelAbrahams | 129
microsoft/typescript | yuit | 116