In addition to the recommendations made in other answer, do note a few things:

• ADM can intercept downloads from within its own browser, not from other apps.
• Apps which depend on Android's activity resolver (to show chooser dialog or "Complete action using" by sending an implicit intent) can forward downloadable links to ADM (and other apps which register preferred activities as downloaders).

Apps can also query available activities for a certain intent (action, path and/or mime) type and then send explicit intent to an app chosen by user. E.g. Firefox looks for system's preferred activities for a given URL and mime type and maintains its own download preferences for all mime types.

ADM - in its AndroidManifest.xml file - registers itself for android.intent.action.VIEW, category DEFAULT/BROWSABLE, scheme http/https, all mime types and a long list of file extensions. So do other apps like MiXplorer and Firefox itself. Therefore they appears as eligible candidates when (an app through) OS looks for a downloader/browser.

• Xposed module "Download Redirection" can intercept all downloads which are forwarded by apps to Android's Download Manager (com.android.providers.downloads).
• But for apps which use their internal downloader, links need to be shared to ADM or copied to clipboard so that ADM can intercept them.

RELATED:

• Alternative “File Open” - how ”ResolverActivity” works?

In addition to the recommendations made in other answer, do note a few things:

• ADM can intercept downloads from within its own browser, not from other apps, except from those which are looking for a browser/downloader app.

• Apps which depend on Android's activity resolver (to show chooser dialog or "Complete action using" by sending an implicit intent) can forward downloadable links to ADM (and other apps which register preferred activities as downloaders).

  Apps can also query available activities for a certain intent (action, path and/or mime) type and then send explicit intent to an app chosen by user. E.g. Firefox looks for system's preferred activities for a given URL and mime type and maintains its own download preferences for all mime types.

  ADM - in its AndroidManifest.xml file - registers itself for android.intent.action.VIEW, category DEFAULT/BROWSABLE, scheme http/https, all mime types and a long list of file extensions. So do other apps like MiXplorer and Firefox itself. Therefore they appears as eligible candidates when (an app through) OS looks for a downloader/browser.

• Xposed module "Download Redirection" can intercept all downloads which are forwarded by apps to Android's Download Manager (com.android.providers.downloads).

• But for apps which use their internal downloader, links need to be shared to ADM or copied to clipboard so that ADM can intercept them.

RELATED:

• Alternative “File Open” - how ”ResolverActivity” works?

In addition to the recommendation made in other answer, do note a few things:

• ADM can intercept downloads from within its own browser, not from other apps.
• Apps which open Android's resolver activity (Complete action using) can forward downloadable links to ADM (and other apps which register preferred activities as downloaders).

Firefox looks for system's preferred activities for a given URL and mime type and maintains its own download preferences for all mime types.

• Xposed module "Download Redirection" can intercept all downloads which are forwarded by apps to Android's Download Manager (com.android.providers.downloads).
• But for apps which use their internal downloader, links need to be shared to ADM or copied to clipboard so that ADM can intercept them.

In addition to the recommendations made in other answer, do note a few things:

• ADM can intercept downloads from within its own browser, not from other apps.
• Apps which depend on Android's activity resolver (to show chooser dialog or "Complete action using" by sending an implicit intent) can forward downloadable links to ADM (and other apps which register preferred activities as downloaders).

Apps can also query available activities for a certain intent (action, path and/or mime) type and then send explicit intent to an app chosen by user. E.g. Firefox looks for system's preferred activities for a given URL and mime type and maintains its own download preferences for all mime types.

ADM - in its AndroidManifest.xml file - registers itself for android.intent.action.VIEW, category DEFAULT/BROWSABLE, scheme http/https, all mime types and a long list of file extensions. So do other apps like MiXplorer and Firefox itself. Therefore they appears as eligible candidates when (an app through) OS looks for a downloader/browser.

• Xposed module "Download Redirection" can intercept all downloads which are forwarded by apps to Android's Download Manager (com.android.providers.downloads).
• But for apps which use their internal downloader, links need to be shared to ADM or copied to clipboard so that ADM can intercept them.

RELATED:

• Alternative “File Open” - how ”ResolverActivity” works?