The small bundle of files referred to as "the amalgamation" does not contain source files such as test_md5.c ; it only has
```
> unzip -v sqlite-amalgamation-3300100.zip
Archive: sqlite-amalgamation-3300100.zip
Length Method Size Cmpr Date Time CRC-32 Name
-------- ------ ------- ---- ---------- ----- -------- ----
0 Stored 0 0% 10/11/2019 07:26 00000000 sqlite-amalgamation-3300100/
7947211 Defl:N 2050426 74% 10/11/2019 07:26 beace389 sqlite-amalgamation-3300100/sqlite3.c
588681 Defl:N 148854 75% 10/11/2019 07:26 977b314b sqlite-amalgamation-3300100/shell.c
34156 Defl:N 6012 82% 10/11/2019 07:26 cd5c3e82 sqlite-amalgamation-3300100/sqlite3ext.h
564824 Defl:N 146169 74% 10/11/2019 07:26 29978aed sqlite-amalgamation-3300100/sqlite3.h
-------- ------- --- -------
9134872 2351461 74% 5 files
>
```
Peruse near the bottom of the download page for "Source Code Repositories". From there, you should be able to get to the files that go into the amalgamation.